Calculus Examples

Find the Local Maxima and Minima f(x)=4px^2+804.248/x
Step 1
Find the first derivative of the function.
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Step 1.1
By the Sum Rule, the derivative of with respect to is .
Step 1.2
Evaluate .
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Step 1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.2
Differentiate using the Power Rule which states that is where .
Step 1.2.3
Multiply by .
Step 1.3
Evaluate .
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Step 1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.3.2
Rewrite as .
Step 1.3.3
Differentiate using the Power Rule which states that is where .
Step 1.3.4
Multiply by .
Step 1.4
Simplify.
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Step 1.4.1
Rewrite the expression using the negative exponent rule .
Step 1.4.2
Combine terms.
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Step 1.4.2.1
Combine and .
Step 1.4.2.2
Move the negative in front of the fraction.
Step 2
Find the second derivative of the function.
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Step 2.1
By the Sum Rule, the derivative of with respect to is .
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
Differentiate using the Power Rule which states that is where .
Step 2.2.3
Multiply by .
Step 2.3
Evaluate .
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Step 2.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 2.3.2
Rewrite as .
Step 2.3.3
Differentiate using the chain rule, which states that is where and .
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Step 2.3.3.1
To apply the Chain Rule, set as .
Step 2.3.3.2
Differentiate using the Power Rule which states that is where .
Step 2.3.3.3
Replace all occurrences of with .
Step 2.3.4
Differentiate using the Power Rule which states that is where .
Step 2.3.5
Multiply the exponents in .
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Step 2.3.5.1
Apply the power rule and multiply exponents, .
Step 2.3.5.2
Multiply by .
Step 2.3.6
Multiply by .
Step 2.3.7
Raise to the power of .
Step 2.3.8
Use the power rule to combine exponents.
Step 2.3.9
Subtract from .
Step 2.3.10
Multiply by .
Step 2.4
Simplify.
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Step 2.4.1
Rewrite the expression using the negative exponent rule .
Step 2.4.2
Combine and .
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
By the Sum Rule, the derivative of with respect to is .
Step 4.1.2
Evaluate .
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Step 4.1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.2.2
Differentiate using the Power Rule which states that is where .
Step 4.1.2.3
Multiply by .
Step 4.1.3
Evaluate .
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Step 4.1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 4.1.3.2
Rewrite as .
Step 4.1.3.3
Differentiate using the Power Rule which states that is where .
Step 4.1.3.4
Multiply by .
Step 4.1.4
Simplify.
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Step 4.1.4.1
Rewrite the expression using the negative exponent rule .
Step 4.1.4.2
Combine terms.
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Step 4.1.4.2.1
Combine and .
Step 4.1.4.2.2
Move the negative in front of the fraction.
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
Find the LCD of the terms in the equation.
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Step 5.2.1
Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.
Step 5.2.2
The LCM of one and any expression is the expression.
Step 5.3
Multiply each term in by to eliminate the fractions.
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Step 5.3.1
Multiply each term in by .
Step 5.3.2
Simplify the left side.
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Step 5.3.2.1
Simplify each term.
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Step 5.3.2.1.1
Multiply by by adding the exponents.
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Step 5.3.2.1.1.1
Move .
Step 5.3.2.1.1.2
Multiply by .
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Step 5.3.2.1.1.2.1
Raise to the power of .
Step 5.3.2.1.1.2.2
Use the power rule to combine exponents.
Step 5.3.2.1.1.3
Add and .
Step 5.3.2.1.2
Cancel the common factor of .
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Step 5.3.2.1.2.1
Move the leading negative in into the numerator.
Step 5.3.2.1.2.2
Cancel the common factor.
Step 5.3.2.1.2.3
Rewrite the expression.
Step 5.3.3
Simplify the right side.
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Step 5.3.3.1
Multiply by .
Step 5.4
Solve the equation.
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Step 5.4.1
Add to both sides of the equation.
Step 5.4.2
Divide each term in by and simplify.
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Step 5.4.2.1
Divide each term in by .
Step 5.4.2.2
Simplify the left side.
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Step 5.4.2.2.1
Cancel the common factor of .
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Step 5.4.2.2.1.1
Cancel the common factor.
Step 5.4.2.2.1.2
Rewrite the expression.
Step 5.4.2.2.2
Cancel the common factor of .
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Step 5.4.2.2.2.1
Cancel the common factor.
Step 5.4.2.2.2.2
Divide by .
Step 5.4.2.3
Simplify the right side.
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Step 5.4.2.3.1
Factor out of .
Step 5.4.2.3.2
Factor out of .
Step 5.4.2.3.3
Separate fractions.
Step 5.4.2.3.4
Divide by .
Step 5.4.2.3.5
Combine and .
Step 5.4.3
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 5.4.4
Simplify .
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Step 5.4.4.1
Rewrite as .
Step 5.4.4.2
Multiply by .
Step 5.4.4.3
Combine and simplify the denominator.
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Step 5.4.4.3.1
Multiply by .
Step 5.4.4.3.2
Raise to the power of .
Step 5.4.4.3.3
Use the power rule to combine exponents.
Step 5.4.4.3.4
Add and .
Step 5.4.4.3.5
Rewrite as .
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Step 5.4.4.3.5.1
Use to rewrite as .
Step 5.4.4.3.5.2
Apply the power rule and multiply exponents, .
Step 5.4.4.3.5.3
Combine and .
Step 5.4.4.3.5.4
Cancel the common factor of .
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Step 5.4.4.3.5.4.1
Cancel the common factor.
Step 5.4.4.3.5.4.2
Rewrite the expression.
Step 5.4.4.3.5.5
Simplify.
Step 5.4.4.4
Rewrite as .
Step 5.4.4.5
Combine using the product rule for radicals.
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
Solve for .
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Step 6.2.1
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 6.2.2
Simplify .
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Step 6.2.2.1
Rewrite as .
Step 6.2.2.2
Pull terms out from under the radical, assuming positive real numbers.
Step 6.2.2.3
Plus or minus is .
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 each term.
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Step 9.1.1
Simplify the denominator.
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Step 9.1.1.1
Apply the product rule to .
Step 9.1.1.2
Rewrite as .
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Step 9.1.1.2.1
Use to rewrite as .
Step 9.1.1.2.2
Apply the power rule and multiply exponents, .
Step 9.1.1.2.3
Combine and .
Step 9.1.1.2.4
Cancel the common factor of .
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Step 9.1.1.2.4.1
Cancel the common factor.
Step 9.1.1.2.4.2
Rewrite the expression.
Step 9.1.1.2.5
Simplify.
Step 9.1.1.3
Cancel the common factor of and .
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Step 9.1.1.3.1
Factor out of .
Step 9.1.1.3.2
Cancel the common factors.
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Step 9.1.1.3.2.1
Factor out of .
Step 9.1.1.3.2.2
Cancel the common factor.
Step 9.1.1.3.2.3
Rewrite the expression.
Step 9.1.2
Multiply the numerator by the reciprocal of the denominator.
Step 9.1.3
Cancel the common factor of .
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Step 9.1.3.1
Factor out of .
Step 9.1.3.2
Cancel the common factor.
Step 9.1.3.3
Rewrite the expression.
Step 9.2
Add and .
Step 10
Since the first derivative test failed, there are no local extrema.
No Local Extrema
Step 11