Calculus Examples

Find the Local Maxima and Minima P(x) = natural log of -x^3+12x^2+27x+1
Step 1
Find the first derivative of the function.
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Step 1.1
Differentiate using the chain rule, which states that is where and .
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Step 1.1.1
To apply the Chain Rule, set as .
Step 1.1.2
The derivative of with respect to is .
Step 1.1.3
Replace all occurrences of with .
Step 1.2
Differentiate.
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Step 1.2.1
By the Sum Rule, the derivative of with respect to is .
Step 1.2.2
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.3
Differentiate using the Power Rule which states that is where .
Step 1.2.4
Multiply by .
Step 1.2.5
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.6
Differentiate using the Power Rule which states that is where .
Step 1.2.7
Multiply by .
Step 1.2.8
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.9
Differentiate using the Power Rule which states that is where .
Step 1.2.10
Multiply by .
Step 1.2.11
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.12
Add and .
Step 1.3
Simplify.
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Step 1.3.1
Reorder the factors of .
Step 1.3.2
Multiply by .
Step 1.3.3
Simplify the numerator.
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Step 1.3.3.1
Factor out of .
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Step 1.3.3.1.1
Factor out of .
Step 1.3.3.1.2
Factor out of .
Step 1.3.3.1.3
Factor out of .
Step 1.3.3.1.4
Factor out of .
Step 1.3.3.1.5
Factor out of .
Step 1.3.3.2
Factor by grouping.
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Step 1.3.3.2.1
For a polynomial of the form , rewrite the middle term as a sum of two terms whose product is and whose sum is .
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Step 1.3.3.2.1.1
Factor out of .
Step 1.3.3.2.1.2
Rewrite as plus
Step 1.3.3.2.1.3
Apply the distributive property.
Step 1.3.3.2.2
Factor out the greatest common factor from each group.
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Step 1.3.3.2.2.1
Group the first two terms and the last two terms.
Step 1.3.3.2.2.2
Factor out the greatest common factor (GCF) from each group.
Step 1.3.3.2.3
Factor the polynomial by factoring out the greatest common factor, .
Step 1.3.4
Factor out of .
Step 1.3.5
Rewrite as .
Step 1.3.6
Factor out of .
Step 1.3.7
Rewrite as .
Step 1.3.8
Factor out of .
Step 1.3.9
Factor out of .
Step 1.3.10
Factor out of .
Step 1.3.11
Factor out of .
Step 1.3.12
Factor out of .
Step 1.3.13
Rewrite as .
Step 1.3.14
Factor out of .
Step 1.3.15
Rewrite as .
Step 1.3.16
Cancel the common factor.
Step 1.3.17
Rewrite the expression.
Step 2
Find the second derivative of the function.
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Step 2.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.2
Differentiate using the Quotient Rule which states that is where and .
Step 2.3
Differentiate using the Product Rule which states that is where and .
Step 2.4
Differentiate.
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Step 2.4.1
By the Sum Rule, the derivative of with respect to is .
Step 2.4.2
Differentiate using the Power Rule which states that is where .
Step 2.4.3
Since is constant with respect to , the derivative of with respect to is .
Step 2.4.4
Simplify the expression.
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Step 2.4.4.1
Add and .
Step 2.4.4.2
Multiply by .
Step 2.4.5
By the Sum Rule, the derivative of with respect to is .
Step 2.4.6
Differentiate using the Power Rule which states that is where .
Step 2.4.7
Since is constant with respect to , the derivative of with respect to is .
Step 2.4.8
Simplify by adding terms.
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Step 2.4.8.1
Add and .
Step 2.4.8.2
Multiply by .
Step 2.4.8.3
Add and .
Step 2.4.8.4
Subtract from .
Step 2.4.9
By the Sum Rule, the derivative of with respect to is .
Step 2.4.10
Differentiate using the Power Rule which states that is where .
Step 2.4.11
Since is constant with respect to , the derivative of with respect to is .
Step 2.4.12
Differentiate using the Power Rule which states that is where .
Step 2.4.13
Multiply by .
Step 2.4.14
Since is constant with respect to , the derivative of with respect to is .
Step 2.4.15
Differentiate using the Power Rule which states that is where .
Step 2.4.16
Multiply by .
Step 2.4.17
Since is constant with respect to , the derivative of with respect to is .
Step 2.4.18
Combine fractions.
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Step 2.4.18.1
Add and .
Step 2.4.18.2
Combine and .
Step 2.5
Simplify.
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Step 2.5.1
Apply the distributive property.
Step 2.5.2
Apply the distributive property.
Step 2.5.3
Simplify the numerator.
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Step 2.5.3.1
Simplify each term.
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Step 2.5.3.1.1
Expand by multiplying each term in the first expression by each term in the second expression.
Step 2.5.3.1.2
Simplify each term.
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Step 2.5.3.1.2.1
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.2.2
Multiply by by adding the exponents.
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Step 2.5.3.1.2.2.1
Move .
Step 2.5.3.1.2.2.2
Multiply by .
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Step 2.5.3.1.2.2.2.1
Raise to the power of .
Step 2.5.3.1.2.2.2.2
Use the power rule to combine exponents.
Step 2.5.3.1.2.2.3
Add and .
Step 2.5.3.1.2.3
Move to the left of .
Step 2.5.3.1.2.4
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.2.5
Multiply by by adding the exponents.
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Step 2.5.3.1.2.5.1
Move .
Step 2.5.3.1.2.5.2
Multiply by .
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Step 2.5.3.1.2.5.2.1
Raise to the power of .
Step 2.5.3.1.2.5.2.2
Use the power rule to combine exponents.
Step 2.5.3.1.2.5.3
Add and .
Step 2.5.3.1.2.6
Multiply by .
Step 2.5.3.1.2.7
Multiply by .
Step 2.5.3.1.2.8
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.2.9
Multiply by by adding the exponents.
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Step 2.5.3.1.2.9.1
Move .
Step 2.5.3.1.2.9.2
Multiply by .
Step 2.5.3.1.2.10
Multiply by .
Step 2.5.3.1.2.11
Multiply by .
Step 2.5.3.1.2.12
Multiply by .
Step 2.5.3.1.2.13
Multiply by .
Step 2.5.3.1.3
Subtract from .
Step 2.5.3.1.4
Subtract from .
Step 2.5.3.1.5
Subtract from .
Step 2.5.3.1.6
Apply the distributive property.
Step 2.5.3.1.7
Simplify.
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Step 2.5.3.1.7.1
Multiply by .
Step 2.5.3.1.7.2
Multiply by .
Step 2.5.3.1.7.3
Multiply by .
Step 2.5.3.1.7.4
Multiply by .
Step 2.5.3.1.7.5
Multiply by .
Step 2.5.3.1.8
Multiply by .
Step 2.5.3.1.9
Expand using the FOIL Method.
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Step 2.5.3.1.9.1
Apply the distributive property.
Step 2.5.3.1.9.2
Apply the distributive property.
Step 2.5.3.1.9.3
Apply the distributive property.
Step 2.5.3.1.10
Simplify and combine like terms.
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Step 2.5.3.1.10.1
Simplify each term.
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Step 2.5.3.1.10.1.1
Multiply by by adding the exponents.
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Step 2.5.3.1.10.1.1.1
Move .
Step 2.5.3.1.10.1.1.2
Multiply by .
Step 2.5.3.1.10.1.2
Multiply by .
Step 2.5.3.1.10.1.3
Rewrite as .
Step 2.5.3.1.10.1.4
Multiply by .
Step 2.5.3.1.10.2
Subtract from .
Step 2.5.3.1.11
Expand by multiplying each term in the first expression by each term in the second expression.
Step 2.5.3.1.12
Simplify each term.
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Step 2.5.3.1.12.1
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.12.2
Multiply by by adding the exponents.
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Step 2.5.3.1.12.2.1
Move .
Step 2.5.3.1.12.2.2
Use the power rule to combine exponents.
Step 2.5.3.1.12.2.3
Add and .
Step 2.5.3.1.12.3
Multiply by .
Step 2.5.3.1.12.4
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.12.5
Multiply by by adding the exponents.
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Step 2.5.3.1.12.5.1
Move .
Step 2.5.3.1.12.5.2
Multiply by .
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Step 2.5.3.1.12.5.2.1
Raise to the power of .
Step 2.5.3.1.12.5.2.2
Use the power rule to combine exponents.
Step 2.5.3.1.12.5.3
Add and .
Step 2.5.3.1.12.6
Multiply by .
Step 2.5.3.1.12.7
Multiply by .
Step 2.5.3.1.12.8
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.12.9
Multiply by by adding the exponents.
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Step 2.5.3.1.12.9.1
Move .
Step 2.5.3.1.12.9.2
Multiply by .
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Step 2.5.3.1.12.9.2.1
Raise to the power of .
Step 2.5.3.1.12.9.2.2
Use the power rule to combine exponents.
Step 2.5.3.1.12.9.3
Add and .
Step 2.5.3.1.12.10
Multiply by .
Step 2.5.3.1.12.11
Rewrite using the commutative property of multiplication.
Step 2.5.3.1.12.12
Multiply by by adding the exponents.
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Step 2.5.3.1.12.12.1
Move .
Step 2.5.3.1.12.12.2
Multiply by .
Step 2.5.3.1.12.13
Multiply by .
Step 2.5.3.1.12.14
Multiply by .
Step 2.5.3.1.12.15
Multiply by .
Step 2.5.3.1.12.16
Multiply by .
Step 2.5.3.1.12.17
Multiply by .
Step 2.5.3.1.13
Add and .
Step 2.5.3.1.14
Subtract from .
Step 2.5.3.1.15
Add and .
Step 2.5.3.1.16
Subtract from .
Step 2.5.3.1.17
Apply the distributive property.
Step 2.5.3.1.18
Simplify.
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Step 2.5.3.1.18.1
Multiply by .
Step 2.5.3.1.18.2
Multiply by .
Step 2.5.3.1.18.3
Multiply by .
Step 2.5.3.1.18.4
Multiply by .
Step 2.5.3.1.18.5
Multiply by .
Step 2.5.3.2
Subtract from .
Step 2.5.3.3
Add and .
Step 2.5.3.4
Subtract from .
Step 2.5.3.5
Subtract from .
Step 2.5.3.6
Subtract from .
Step 2.5.4
Factor out of .
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Step 2.5.4.1
Factor out of .
Step 2.5.4.2
Factor out of .
Step 2.5.4.3
Factor out of .
Step 2.5.4.4
Factor out of .
Step 2.5.4.5
Factor out of .
Step 2.5.4.6
Factor out of .
Step 2.5.4.7
Factor out of .
Step 2.5.4.8
Factor out of .
Step 2.5.4.9
Factor out of .
Step 2.5.5
Factor out of .
Step 2.5.6
Factor out of .
Step 2.5.7
Factor out of .
Step 2.5.8
Factor out of .
Step 2.5.9
Factor out of .
Step 2.5.10
Factor out of .
Step 2.5.11
Factor out of .
Step 2.5.12
Rewrite as .
Step 2.5.13
Factor out of .
Step 2.5.14
Rewrite as .
Step 2.5.15
Move the negative in front of the fraction.
Step 3
To find the local maximum and minimum values of the function, set the derivative equal to and solve.
Step 4
Find the first derivative.
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Step 4.1
Find the first derivative.
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Step 4.1.1
Differentiate using the chain rule, which states that is where and .
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Step 4.1.1.1
To apply the Chain Rule, set as .
Step 4.1.1.2
The derivative of with respect to is .
Step 4.1.1.3
Replace all occurrences of with .
Step 4.1.2
Differentiate.
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Step 4.1.2.1
By the Sum Rule, the derivative of with respect to is .
Step 4.1.2.2
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.2.3
Differentiate using the Power Rule which states that is where .
Step 4.1.2.4
Multiply by .
Step 4.1.2.5
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.2.6
Differentiate using the Power Rule which states that is where .
Step 4.1.2.7
Multiply by .
Step 4.1.2.8
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.2.9
Differentiate using the Power Rule which states that is where .
Step 4.1.2.10
Multiply by .
Step 4.1.2.11
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.2.12
Add and .
Step 4.1.3
Simplify.
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Step 4.1.3.1
Reorder the factors of .
Step 4.1.3.2
Multiply by .
Step 4.1.3.3
Simplify the numerator.
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Step 4.1.3.3.1
Factor out of .
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Step 4.1.3.3.1.1
Factor out of .
Step 4.1.3.3.1.2
Factor out of .
Step 4.1.3.3.1.3
Factor out of .
Step 4.1.3.3.1.4
Factor out of .
Step 4.1.3.3.1.5
Factor out of .
Step 4.1.3.3.2
Factor by grouping.
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Step 4.1.3.3.2.1
For a polynomial of the form , rewrite the middle term as a sum of two terms whose product is and whose sum is .
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Step 4.1.3.3.2.1.1
Factor out of .
Step 4.1.3.3.2.1.2
Rewrite as plus
Step 4.1.3.3.2.1.3
Apply the distributive property.
Step 4.1.3.3.2.2
Factor out the greatest common factor from each group.
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Step 4.1.3.3.2.2.1
Group the first two terms and the last two terms.
Step 4.1.3.3.2.2.2
Factor out the greatest common factor (GCF) from each group.
Step 4.1.3.3.2.3
Factor the polynomial by factoring out the greatest common factor, .
Step 4.1.3.4
Factor out of .
Step 4.1.3.5
Rewrite as .
Step 4.1.3.6
Factor out of .
Step 4.1.3.7
Rewrite as .
Step 4.1.3.8
Factor out of .
Step 4.1.3.9
Factor out of .
Step 4.1.3.10
Factor out of .
Step 4.1.3.11
Factor out of .
Step 4.1.3.12
Factor out of .
Step 4.1.3.13
Rewrite as .
Step 4.1.3.14
Factor out of .
Step 4.1.3.15
Rewrite as .
Step 4.1.3.16
Cancel the common factor.
Step 4.1.3.17
Rewrite the expression.
Step 4.2
The first derivative of with respect to is .
Step 5
Set the first derivative equal to then solve the equation .
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Step 5.1
Set the first derivative equal to .
Step 5.2
Set the numerator equal to zero.
Step 5.3
Solve the equation for .
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Step 5.3.1
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 5.3.2
Set equal to and solve for .
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Step 5.3.2.1
Set equal to .
Step 5.3.2.2
Subtract from both sides of the equation.
Step 5.3.3
Set equal to and solve for .
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Step 5.3.3.1
Set equal to .
Step 5.3.3.2
Add to both sides of the equation.
Step 5.3.4
The final solution is all the values that make true.
Step 6
Find the values where the derivative is undefined.
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Step 6.1
Set the denominator in equal to to find where the expression is undefined.
Step 6.2
Graph each side of the equation. The solution is the x-value of the point of intersection.
Step 6.3
The equation is undefined where the denominator equals , the argument of a square root is less than , or the argument of a logarithm is less than or equal to .
Step 7
Critical points to evaluate.
Step 8
Evaluate the second derivative at . If the second derivative is positive, then this is a local minimum. If it is negative, then this is a local maximum.
Step 9
Evaluate the second derivative.
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Step 9.1
Simplify the numerator.
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Step 9.1.1
Raise to the power of .
Step 9.1.2
Raise to the power of .
Step 9.1.3
Multiply by .
Step 9.1.4
Raise to the power of .
Step 9.1.5
Multiply by .
Step 9.1.6
Multiply by .
Step 9.1.7
Subtract from .
Step 9.1.8
Add and .
Step 9.1.9
Add and .
Step 9.1.10
Add and .
Step 9.2
Simplify the denominator.
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Step 9.2.1
Raise to the power of .
Step 9.2.2
Raise to the power of .
Step 9.2.3
Multiply by .
Step 9.2.4
Multiply by .
Step 9.2.5
Subtract from .
Step 9.2.6
Subtract from .
Step 9.2.7
Subtract from .
Step 9.2.8
Raise to the power of .
Step 9.3
Reduce the expression by cancelling the common factors.
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Step 9.3.1
Multiply by .
Step 9.3.2
Cancel the common factor of and .
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Step 9.3.2.1
Factor out of .
Step 9.3.2.2
Cancel the common factors.
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Step 9.3.2.2.1
Factor out of .
Step 9.3.2.2.2
Cancel the common factor.
Step 9.3.2.2.3
Rewrite the expression.
Step 10
is a local maximum because the value of the second derivative is negative. This is referred to as the second derivative test.
is a local maximum
Step 11
Find the y-value when .
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Step 11.1
Replace the variable with in the expression.
Step 11.2
Simplify the result.
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Step 11.2.1
Simplify each term.
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Step 11.2.1.1
Raise to the power of .
Step 11.2.1.2
Multiply by .
Step 11.2.1.3
Raise to the power of .
Step 11.2.1.4
Multiply by .
Step 11.2.1.5
Multiply by .
Step 11.2.2
Simplify by adding numbers.
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Step 11.2.2.1
Add and .
Step 11.2.2.2
Add and .
Step 11.2.2.3
Add and .
Step 11.2.3
The final answer is .
Step 12
Evaluate the second derivative at . If the second derivative is positive, then this is a local minimum. If it is negative, then this is a local maximum.
Step 13
Evaluate the second derivative.
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Step 13.1
Simplify each term.
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Step 13.1.1
Raise to the power of .
Step 13.1.2
Raise to the power of .
Step 13.1.3
Multiply by .
Step 13.1.4
Multiply by .
Step 13.2
Simplify the expression.
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Step 13.2.1
Subtract from .
Step 13.2.2
Add and .
Step 13.2.3
Subtract from .
Step 13.2.4
Raise to the power of .
Step 13.2.5
The expression contains a division by . The expression is undefined.
Undefined
Step 13.3
The expression contains a division by . The expression is undefined.
Undefined
Undefined
Step 14
Since there is at least one point with or undefined second derivative, apply the first derivative test.
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Step 14.1
Split into separate intervals around the values that make the first derivative or undefined.
Step 14.2
Substitute any number, such as , from the interval in the first derivative to check if the result is negative or positive.
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Step 14.2.1
Replace the variable with in the expression.
Step 14.2.2
Simplify the result.
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Step 14.2.2.1
Simplify the numerator.
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Step 14.2.2.1.1
Add and .
Step 14.2.2.1.2
Multiply by .
Step 14.2.2.1.3
Subtract from .
Step 14.2.2.2
Simplify the denominator.
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Step 14.2.2.2.1
Raise to the power of .
Step 14.2.2.2.2
Raise to the power of .
Step 14.2.2.2.3
Multiply by .
Step 14.2.2.2.4
Multiply by .
Step 14.2.2.2.5
Subtract from .
Step 14.2.2.2.6
Add and .
Step 14.2.2.2.7
Subtract from .
Step 14.2.2.3
Simplify the expression.
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Step 14.2.2.3.1
Multiply by .
Step 14.2.2.3.2
Move the negative in front of the fraction.
Step 14.2.2.4
The final answer is .
Step 14.3
Substitute any number, such as , from the interval in the first derivative to check if the result is negative or positive.
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Step 14.3.1
Replace the variable with in the expression.
Step 14.3.2
Simplify the result.
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Step 14.3.2.1
Simplify the numerator.
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Step 14.3.2.1.1
Add and .
Step 14.3.2.1.2
Combine exponents.
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Step 14.3.2.1.2.1
Multiply by .
Step 14.3.2.1.2.2
Multiply by .
Step 14.3.2.2
Simplify the denominator.
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Step 14.3.2.2.1
Raise to the power of .
Step 14.3.2.2.2
Raise to the power of .
Step 14.3.2.2.3
Multiply by .
Step 14.3.2.2.4
Multiply by .
Step 14.3.2.2.5
Subtract from .
Step 14.3.2.2.6
Add and .
Step 14.3.2.2.7
Subtract from .
Step 14.3.2.3
Divide by .
Step 14.3.2.4
The final answer is .
Step 14.4
Substitute any number, such as , from the interval in the first derivative to check if the result is negative or positive.
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Step 14.4.1
Replace the variable with in the expression.
Step 14.4.2
Simplify the result.
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Step 14.4.2.1
Simplify the numerator.
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Step 14.4.2.1.1
Add and .
Step 14.4.2.1.2
Multiply by .
Step 14.4.2.1.3
Subtract from .
Step 14.4.2.2
Simplify the denominator.
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Step 14.4.2.2.1
Raising to any positive power yields .
Step 14.4.2.2.2
Raising to any positive power yields .
Step 14.4.2.2.3
Multiply by .
Step 14.4.2.2.4
Multiply by .
Step 14.4.2.2.5
Add and .
Step 14.4.2.2.6
Add and .
Step 14.4.2.2.7
Subtract from .
Step 14.4.2.3
Simplify the expression.
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Step 14.4.2.3.1
Multiply by .
Step 14.4.2.3.2
Divide by .
Step 14.4.2.4
The final answer is .
Step 14.5
Substitute any number, such as , from the interval in the first derivative to check if the result is negative or positive.
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Step 14.5.1
Replace the variable with in the expression.
Step 14.5.2
Simplify the result.
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Step 14.5.2.1
Simplify the numerator.
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Step 14.5.2.1.1
Add and .
Step 14.5.2.1.2
Multiply by .
Step 14.5.2.1.3
Subtract from .
Step 14.5.2.2
Simplify the denominator.
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Step 14.5.2.2.1
Raise to the power of .
Step 14.5.2.2.2
Raise to the power of .
Step 14.5.2.2.3
Multiply by .
Step 14.5.2.2.4
Multiply by .
Step 14.5.2.2.5
Subtract from .
Step 14.5.2.2.6
Subtract from .
Step 14.5.2.2.7
Subtract from .
Step 14.5.2.3
Simplify the expression.
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Step 14.5.2.3.1
Multiply by .
Step 14.5.2.3.2
Move the negative in front of the fraction.
Step 14.5.2.4
The final answer is .
Step 14.6
Since the first derivative did not change signs around , this is not a local maximum or minimum.
Not a local maximum or minimum
Step 14.7
Since the first derivative changed signs from negative to positive around , then is a local minimum.
is a local minimum
Step 14.8
Since the first derivative changed signs from positive to negative around , then is a local maximum.
is a local maximum
Step 14.9
These are the local extrema for .
is a local minimum
is a local maximum
is a local minimum
is a local maximum
Step 15