Calculus Examples

Find the Local Maxima and Minima x^2+480/x
Step 1
Write as a function.
Step 2
Find the first derivative of the function.
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Step 2.1
Differentiate.
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Step 2.1.1
By the Sum Rule, the derivative of with respect to is .
Step 2.1.2
Differentiate using the Power Rule which states that is where .
Step 2.2
Evaluate .
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Step 2.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.2.2
Rewrite as .
Step 2.2.3
Differentiate using the Power Rule which states that is where .
Step 2.2.4
Multiply by .
Step 2.3
Simplify.
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Step 2.3.1
Rewrite the expression using the negative exponent rule .
Step 2.3.2
Combine terms.
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Step 2.3.2.1
Combine and .
Step 2.3.2.2
Move the negative in front of the fraction.
Step 3
Find the second derivative of the function.
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Step 3.1
By the Sum Rule, the derivative of with respect to is .
Step 3.2
Evaluate .
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Step 3.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 3.2.2
Differentiate using the Power Rule which states that is where .
Step 3.2.3
Multiply by .
Step 3.3
Evaluate .
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Step 3.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 3.3.2
Rewrite as .
Step 3.3.3
Differentiate using the chain rule, which states that is where and .
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Step 3.3.3.1
To apply the Chain Rule, set as .
Step 3.3.3.2
Differentiate using the Power Rule which states that is where .
Step 3.3.3.3
Replace all occurrences of with .
Step 3.3.4
Differentiate using the Power Rule which states that is where .
Step 3.3.5
Multiply the exponents in .
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Step 3.3.5.1
Apply the power rule and multiply exponents, .
Step 3.3.5.2
Multiply by .
Step 3.3.6
Multiply by .
Step 3.3.7
Raise to the power of .
Step 3.3.8
Use the power rule to combine exponents.
Step 3.3.9
Subtract from .
Step 3.3.10
Multiply by .
Step 3.4
Simplify.
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Step 3.4.1
Rewrite the expression using the negative exponent rule .
Step 3.4.2
Combine and .
Step 3.4.3
Reorder terms.
Step 4
To find the local maximum and minimum values of the function, set the derivative equal to and solve.
Step 5
Find the first derivative.
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Step 5.1
Find the first derivative.
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Step 5.1.1
Differentiate.
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Step 5.1.1.1
By the Sum Rule, the derivative of with respect to is .
Step 5.1.1.2
Differentiate using the Power Rule which states that is where .
Step 5.1.2
Evaluate .
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Step 5.1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 5.1.2.2
Rewrite as .
Step 5.1.2.3
Differentiate using the Power Rule which states that is where .
Step 5.1.2.4
Multiply by .
Step 5.1.3
Simplify.
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Step 5.1.3.1
Rewrite the expression using the negative exponent rule .
Step 5.1.3.2
Combine terms.
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Step 5.1.3.2.1
Combine and .
Step 5.1.3.2.2
Move the negative in front of the fraction.
Step 5.2
The first derivative of with respect to is .
Step 6
Set the first derivative equal to then solve the equation .
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Step 6.1
Set the first derivative equal to .
Step 6.2
Find the LCD of the terms in the equation.
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Step 6.2.1
Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.
Step 6.2.2
The LCM of one and any expression is the expression.
Step 6.3
Multiply each term in by to eliminate the fractions.
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Step 6.3.1
Multiply each term in by .
Step 6.3.2
Simplify the left side.
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Step 6.3.2.1
Simplify each term.
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Step 6.3.2.1.1
Multiply by by adding the exponents.
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Step 6.3.2.1.1.1
Move .
Step 6.3.2.1.1.2
Multiply by .
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Step 6.3.2.1.1.2.1
Raise to the power of .
Step 6.3.2.1.1.2.2
Use the power rule to combine exponents.
Step 6.3.2.1.1.3
Add and .
Step 6.3.2.1.2
Cancel the common factor of .
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Step 6.3.2.1.2.1
Move the leading negative in into the numerator.
Step 6.3.2.1.2.2
Cancel the common factor.
Step 6.3.2.1.2.3
Rewrite the expression.
Step 6.3.3
Simplify the right side.
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Step 6.3.3.1
Multiply by .
Step 6.4
Solve the equation.
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Step 6.4.1
Add to both sides of the equation.
Step 6.4.2
Subtract from both sides of the equation.
Step 6.4.3
Factor out of .
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Step 6.4.3.1
Factor out of .
Step 6.4.3.2
Factor out of .
Step 6.4.3.3
Factor out of .
Step 6.4.4
Divide each term in by and simplify.
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Step 6.4.4.1
Divide each term in by .
Step 6.4.4.2
Simplify the left side.
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Step 6.4.4.2.1
Cancel the common factor of .
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Step 6.4.4.2.1.1
Cancel the common factor.
Step 6.4.4.2.1.2
Divide by .
Step 6.4.4.3
Simplify the right side.
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Step 6.4.4.3.1
Divide by .
Step 6.4.5
Add to both sides of the equation.
Step 6.4.6
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 6.4.7
Simplify .
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Step 6.4.7.1
Rewrite as .
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Step 6.4.7.1.1
Factor out of .
Step 6.4.7.1.2
Rewrite as .
Step 6.4.7.2
Pull terms out from under the radical.
Step 7
Find the values where the derivative is undefined.
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Step 7.1
Set the denominator in equal to to find where the expression is undefined.
Step 7.2
Solve for .
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Step 7.2.1
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 7.2.2
Simplify .
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Step 7.2.2.1
Rewrite as .
Step 7.2.2.2
Pull terms out from under the radical, assuming positive real numbers.
Step 7.2.2.3
Plus or minus is .
Step 8
Critical points to evaluate.
Step 9
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 10
Evaluate the second derivative.
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Step 10.1
Simplify each term.
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Step 10.1.1
Simplify the denominator.
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Step 10.1.1.1
Apply the product rule to .
Step 10.1.1.2
Raise to the power of .
Step 10.1.1.3
Rewrite as .
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Step 10.1.1.3.1
Use to rewrite as .
Step 10.1.1.3.2
Apply the power rule and multiply exponents, .
Step 10.1.1.3.3
Combine and .
Step 10.1.1.3.4
Cancel the common factor of .
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Step 10.1.1.3.4.1
Cancel the common factor.
Step 10.1.1.3.4.2
Rewrite the expression.
Step 10.1.1.3.5
Evaluate the exponent.
Step 10.1.2
Multiply by .
Step 10.1.3
Divide by .
Step 10.2
Add and .
Step 11
is a local minimum because the value of the second derivative is positive. This is referred to as the second derivative test.
is a local minimum
Step 12
Find the y-value when .
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Step 12.1
Replace the variable with in the expression.
Step 12.2
Simplify the result.
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Step 12.2.1
Simplify each term.
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Step 12.2.1.1
Apply the product rule to .
Step 12.2.1.2
Raise to the power of .
Step 12.2.1.3
Rewrite as .
Step 12.2.1.4
Raise to the power of .
Step 12.2.1.5
Cancel the common factor of and .
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Step 12.2.1.5.1
Factor out of .
Step 12.2.1.5.2
Cancel the common factors.
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Step 12.2.1.5.2.1
Factor out of .
Step 12.2.1.5.2.2
Cancel the common factor.
Step 12.2.1.5.2.3
Rewrite the expression.
Step 12.2.1.6
Multiply by .
Step 12.2.1.7
Combine and simplify the denominator.
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Step 12.2.1.7.1
Multiply by .
Step 12.2.1.7.2
Raise to the power of .
Step 12.2.1.7.3
Use the power rule to combine exponents.
Step 12.2.1.7.4
Add and .
Step 12.2.1.7.5
Rewrite as .
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Step 12.2.1.7.5.1
Use to rewrite as .
Step 12.2.1.7.5.2
Apply the power rule and multiply exponents, .
Step 12.2.1.7.5.3
Combine and .
Step 12.2.1.7.5.4
Cancel the common factor of .
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Step 12.2.1.7.5.4.1
Cancel the common factor.
Step 12.2.1.7.5.4.2
Rewrite the expression.
Step 12.2.1.7.5.5
Evaluate the exponent.
Step 12.2.1.8
Cancel the common factor of and .
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Step 12.2.1.8.1
Factor out of .
Step 12.2.1.8.2
Cancel the common factors.
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Step 12.2.1.8.2.1
Factor out of .
Step 12.2.1.8.2.2
Cancel the common factor.
Step 12.2.1.8.2.3
Rewrite the expression.
Step 12.2.1.8.2.4
Divide by .
Step 12.2.1.9
Rewrite as .
Step 12.2.1.10
Raise to the power of .
Step 12.2.2
Add and .
Step 12.2.3
The final answer is .
Step 13
These are the local extrema for .
is a local minima
Step 14