# Calculus Examples

Step 1
Find the second derivative.
Step 1.1
Find the first derivative.
Step 1.1.1
By the Sum Rule, the derivative of with respect to is .
Step 1.1.2
Evaluate .
Step 1.1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.2.2
Differentiate using the Power Rule which states that is where .
Step 1.1.2.3
Multiply by .
Step 1.1.3
Evaluate .
Step 1.1.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.3.2
Differentiate using the Power Rule which states that is where .
Step 1.1.3.3
Multiply by .
Step 1.2
Find the second derivative.
Step 1.2.1
By the Sum Rule, the derivative of with respect to is .
Step 1.2.2
Evaluate .
Step 1.2.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.2.2
Differentiate using the Power Rule which states that is where .
Step 1.2.2.3
Multiply by .
Step 1.2.3
Evaluate .
Step 1.2.3.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.2.3.2
Differentiate using the Power Rule which states that is where .
Step 1.2.3.3
Multiply by .
Step 1.3
The second derivative of with respect to is .
Step 2
Set the second derivative equal to then solve the equation .
Step 2.1
Set the second derivative equal to .
Step 2.2
Add to both sides of the equation.
Step 2.3
Divide each term in by and simplify.
Step 2.3.1
Divide each term in by .
Step 2.3.2
Simplify the left side.
Step 2.3.2.1
Cancel the common factor of .
Step 2.3.2.1.1
Cancel the common factor.
Step 2.3.2.1.2
Divide by .
Step 2.3.3
Simplify the right side.
Step 2.3.3.1
Cancel the common factor of and .
Step 2.3.3.1.1
Factor out of .
Step 2.3.3.1.2
Cancel the common factors.
Step 2.3.3.1.2.1
Factor out of .
Step 2.3.3.1.2.2
Cancel the common factor.
Step 2.3.3.1.2.3
Rewrite the expression.
Step 3
Find the points where the second derivative is .
Step 3.1
Substitute in to find the value of .
Step 3.1.1
Replace the variable with in the expression.
Step 3.1.2
Simplify the result.
Step 3.1.2.1
Simplify each term.
Step 3.1.2.1.1
Apply the product rule to .
Step 3.1.2.1.2
One to any power is one.
Step 3.1.2.1.3
Raise to the power of .
Step 3.1.2.1.4
Combine and .
Step 3.1.2.1.5
Apply the product rule to .
Step 3.1.2.1.6
One to any power is one.
Step 3.1.2.1.7
Raise to the power of .
Step 3.1.2.1.8
Combine and .
Step 3.1.2.1.9
Move the negative in front of the fraction.
Step 3.1.2.2
To write as a fraction with a common denominator, multiply by .
Step 3.1.2.3
Write each expression with a common denominator of , by multiplying each by an appropriate factor of .
Step 3.1.2.3.1
Multiply by .
Step 3.1.2.3.2
Multiply by .
Step 3.1.2.4
Combine the numerators over the common denominator.
Step 3.1.2.5
Simplify the numerator.
Step 3.1.2.5.1
Multiply by .
Step 3.1.2.5.2
Subtract from .
Step 3.1.2.6
Move the negative in front of the fraction.
Step 3.1.2.7
Step 3.2
The point found by substituting in is . This point can be an inflection point.
Step 4
Split into intervals around the points that could potentially be inflection points.
Step 5
Substitute a value from the interval into the second derivative to determine if it is increasing or decreasing.
Step 5.1
Replace the variable with in the expression.
Step 5.2
Simplify the result.
Step 5.2.1
Multiply by .
Step 5.2.2
Subtract from .
Step 5.2.3
Step 5.3
At , the second derivative is . Since this is negative, the second derivative is decreasing on the interval
Decreasing on since
Decreasing on since
Step 6
Substitute a value from the interval into the second derivative to determine if it is increasing or decreasing.
Step 6.1
Replace the variable with in the expression.
Step 6.2
Simplify the result.
Step 6.2.1
Multiply by .
Step 6.2.2
Subtract from .
Step 6.2.3