Calculus Examples

Find the Absolute Max and Min over the Interval f(x)=-x+cos(3pix) , [0,pi/6]
,
Step 1
Find the critical points.
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Step 1.1
Find the first derivative.
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Step 1.1.1
Find the first derivative.
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Step 1.1.1.1
By the Sum Rule, the derivative of with respect to is .
Step 1.1.1.2
Evaluate .
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Step 1.1.1.2.1
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.1.2.2
Differentiate using the Power Rule which states that is where .
Step 1.1.1.2.3
Multiply by .
Step 1.1.1.3
Evaluate .
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Step 1.1.1.3.1
Differentiate using the chain rule, which states that is where and .
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Step 1.1.1.3.1.1
To apply the Chain Rule, set as .
Step 1.1.1.3.1.2
The derivative of with respect to is .
Step 1.1.1.3.1.3
Replace all occurrences of with .
Step 1.1.1.3.2
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.1.3.3
Differentiate using the Power Rule which states that is where .
Step 1.1.1.3.4
Multiply by .
Step 1.1.1.3.5
Multiply by .
Step 1.1.1.4
Reorder terms.
Step 1.1.2
The first derivative of with respect to is .
Step 1.2
Set the first derivative equal to then solve the equation .
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Step 1.2.1
Set the first derivative equal to .
Step 1.2.2
Add to both sides of the equation.
Step 1.2.3
Divide each term in by and simplify.
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Step 1.2.3.1
Divide each term in by .
Step 1.2.3.2
Simplify the left side.
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Step 1.2.3.2.1
Cancel the common factor of .
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Step 1.2.3.2.1.1
Cancel the common factor.
Step 1.2.3.2.1.2
Rewrite the expression.
Step 1.2.3.2.2
Cancel the common factor of .
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Step 1.2.3.2.2.1
Cancel the common factor.
Step 1.2.3.2.2.2
Divide by .
Step 1.2.3.3
Simplify the right side.
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Step 1.2.3.3.1
Move the negative in front of the fraction.
Step 1.2.4
Take the inverse sine of both sides of the equation to extract from inside the sine.
Step 1.2.5
Simplify the right side.
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Step 1.2.5.1
Evaluate .
Step 1.2.6
Divide each term in by and simplify.
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Step 1.2.6.1
Divide each term in by .
Step 1.2.6.2
Simplify the left side.
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Step 1.2.6.2.1
Cancel the common factor of .
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Step 1.2.6.2.1.1
Cancel the common factor.
Step 1.2.6.2.1.2
Rewrite the expression.
Step 1.2.6.2.2
Cancel the common factor of .
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Step 1.2.6.2.2.1
Cancel the common factor.
Step 1.2.6.2.2.2
Divide by .
Step 1.2.6.3
Simplify the right side.
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Step 1.2.6.3.1
Move the negative in front of the fraction.
Step 1.2.6.3.2
Replace with an approximation.
Step 1.2.6.3.3
Multiply by .
Step 1.2.6.3.4
Divide by .
Step 1.2.6.3.5
Multiply by .
Step 1.2.7
The sine function is negative in the third and fourth quadrants. To find the second solution, subtract the solution from , to find a reference angle. Next, add this reference angle to to find the solution in the third quadrant.
Step 1.2.8
Simplify the expression to find the second solution.
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Step 1.2.8.1
Subtract from .
Step 1.2.8.2
The resulting angle of is positive, less than , and coterminal with .
Step 1.2.8.3
Divide each term in by and simplify.
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Step 1.2.8.3.1
Divide each term in by .
Step 1.2.8.3.2
Simplify the left side.
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Step 1.2.8.3.2.1
Cancel the common factor of .
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Step 1.2.8.3.2.1.1
Cancel the common factor.
Step 1.2.8.3.2.1.2
Rewrite the expression.
Step 1.2.8.3.2.2
Cancel the common factor of .
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Step 1.2.8.3.2.2.1
Cancel the common factor.
Step 1.2.8.3.2.2.2
Divide by .
Step 1.2.8.3.3
Simplify the right side.
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Step 1.2.8.3.3.1
Replace with an approximation.
Step 1.2.8.3.3.2
Multiply by .
Step 1.2.8.3.3.3
Divide by .
Step 1.2.9
Find the period of .
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Step 1.2.9.1
The period of the function can be calculated using .
Step 1.2.9.2
Replace with in the formula for period.
Step 1.2.9.3
is approximately which is positive so remove the absolute value
Step 1.2.9.4
Cancel the common factor of .
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Step 1.2.9.4.1
Cancel the common factor.
Step 1.2.9.4.2
Rewrite the expression.
Step 1.2.10
Add to every negative angle to get positive angles.
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Step 1.2.10.1
Add to to find the positive angle.
Step 1.2.10.2
To write as a fraction with a common denominator, multiply by .
Step 1.2.10.3
Combine fractions.
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Step 1.2.10.3.1
Combine and .
Step 1.2.10.3.2
Combine the numerators over the common denominator.
Step 1.2.10.4
Simplify the numerator.
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Step 1.2.10.4.1
Multiply by .
Step 1.2.10.4.2
Subtract from .
Step 1.2.10.5
Divide by .
Step 1.2.10.6
List the new angles.
Step 1.2.11
The period of the function is so values will repeat every radians in both directions.
, for any integer
, for any integer
Step 1.3
Find the values where the derivative is undefined.
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Step 1.3.1
The domain of the expression is all real numbers except where the expression is undefined. In this case, there is no real number that makes the expression undefined.
Step 1.4
Evaluate at each value where the derivative is or undefined.
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Step 1.4.1
Evaluate at .
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Step 1.4.1.1
Substitute for .
Step 1.4.1.2
Simplify.
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Step 1.4.1.2.1
Simplify each term.
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Step 1.4.1.2.1.1
Multiply by .
Step 1.4.1.2.1.2
Multiply .
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Step 1.4.1.2.1.2.1
Multiply by .
Step 1.4.1.2.1.2.2
Multiply by .
Step 1.4.1.2.2
Add and .
Step 1.4.2
Evaluate at .
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Step 1.4.2.1
Substitute for .
Step 1.4.2.2
Simplify.
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Step 1.4.2.2.1
Simplify each term.
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Step 1.4.2.2.1.1
Multiply by .
Step 1.4.2.2.1.2
Multiply .
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Step 1.4.2.2.1.2.1
Multiply by .
Step 1.4.2.2.1.2.2
Multiply by .
Step 1.4.2.2.2
Add and .
Step 1.4.3
Evaluate at .
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Step 1.4.3.1
Substitute for .
Step 1.4.3.2
Simplify.
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Step 1.4.3.2.1
Simplify each term.
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Step 1.4.3.2.1.1
Multiply by .
Step 1.4.3.2.1.2
Multiply .
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Step 1.4.3.2.1.2.1
Multiply by .
Step 1.4.3.2.1.2.2
Multiply by .
Step 1.4.3.2.2
Add and .
Step 1.4.4
Evaluate at .
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Step 1.4.4.1
Substitute for .
Step 1.4.4.2
Simplify.
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Step 1.4.4.2.1
Simplify each term.
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Step 1.4.4.2.1.1
Multiply by .
Step 1.4.4.2.1.2
Multiply .
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Step 1.4.4.2.1.2.1
Multiply by .
Step 1.4.4.2.1.2.2
Multiply by .
Step 1.4.4.2.2
Add and .
Step 1.4.5
Evaluate at .
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Step 1.4.5.1
Substitute for .
Step 1.4.5.2
Simplify.
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Step 1.4.5.2.1
Simplify each term.
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Step 1.4.5.2.1.1
Multiply by .
Step 1.4.5.2.1.2
Multiply .
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Step 1.4.5.2.1.2.1
Multiply by .
Step 1.4.5.2.1.2.2
Multiply by .
Step 1.4.5.2.2
Add and .
Step 1.4.6
Evaluate at .
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Step 1.4.6.1
Substitute for .
Step 1.4.6.2
Simplify.
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Step 1.4.6.2.1
Simplify each term.
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Step 1.4.6.2.1.1
Multiply by .
Step 1.4.6.2.1.2
Multiply .
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Step 1.4.6.2.1.2.1
Multiply by .
Step 1.4.6.2.1.2.2
Multiply by .
Step 1.4.6.2.2
Add and .
Step 1.4.7
Evaluate at .
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Step 1.4.7.1
Substitute for .
Step 1.4.7.2
Simplify.
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Step 1.4.7.2.1
Simplify each term.
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Step 1.4.7.2.1.1
Multiply by .
Step 1.4.7.2.1.2
Multiply .
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Step 1.4.7.2.1.2.1
Multiply by .
Step 1.4.7.2.1.2.2
Multiply by .
Step 1.4.7.2.2
Add and .
Step 1.4.8
Evaluate at .
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Step 1.4.8.1
Substitute for .
Step 1.4.8.2
Simplify.
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Step 1.4.8.2.1
Simplify each term.
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Step 1.4.8.2.1.1
Multiply by .
Step 1.4.8.2.1.2
Multiply .
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Step 1.4.8.2.1.2.1
Multiply by .
Step 1.4.8.2.1.2.2
Multiply by .
Step 1.4.8.2.2
Add and .
Step 1.4.9
Evaluate at .
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Step 1.4.9.1
Substitute for .
Step 1.4.9.2
Simplify.
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Step 1.4.9.2.1
Simplify each term.
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Step 1.4.9.2.1.1
Multiply by .
Step 1.4.9.2.1.2
Multiply .
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Step 1.4.9.2.1.2.1
Multiply by .
Step 1.4.9.2.1.2.2
Multiply by .
Step 1.4.9.2.2
Add and .
Step 1.4.10
Evaluate at .
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Step 1.4.10.1
Substitute for .
Step 1.4.10.2
Simplify.
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Step 1.4.10.2.1
Simplify each term.
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Step 1.4.10.2.1.1
Multiply by .
Step 1.4.10.2.1.2
Multiply .
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Step 1.4.10.2.1.2.1
Multiply by .
Step 1.4.10.2.1.2.2
Multiply by .
Step 1.4.10.2.2
Add and .
Step 1.4.11
List all of the points.
Step 2
Exclude the points that are not on the interval.
Step 3
Evaluate at the included endpoints.
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Step 3.1
Evaluate at .
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Step 3.1.1
Substitute for .
Step 3.1.2
Simplify.
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Step 3.1.2.1
Simplify each term.
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Step 3.1.2.1.1
Multiply by .
Step 3.1.2.1.2
Multiply .
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Step 3.1.2.1.2.1
Multiply by .
Step 3.1.2.1.2.2
Multiply by .
Step 3.1.2.1.3
The exact value of is .
Step 3.1.2.2
Add and .
Step 3.2
Evaluate at .
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Step 3.2.1
Substitute for .
Step 3.2.2
Simplify.
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Step 3.2.2.1
Simplify each term.
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Step 3.2.2.1.1
Cancel the common factor of .
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Step 3.2.2.1.1.1
Factor out of .
Step 3.2.2.1.1.2
Factor out of .
Step 3.2.2.1.1.3
Cancel the common factor.
Step 3.2.2.1.1.4
Rewrite the expression.
Step 3.2.2.1.2
Combine and .
Step 3.2.2.1.3
Raise to the power of .
Step 3.2.2.1.4
Raise to the power of .
Step 3.2.2.1.5
Use the power rule to combine exponents.
Step 3.2.2.1.6
Add and .
Step 3.2.2.1.7
Evaluate .
Step 3.2.2.2
Add and .
Step 3.3
List all of the points.
Step 4
Compare the values found for each value of in order to determine the absolute maximum and minimum over the given interval. The maximum will occur at the highest value and the minimum will occur at the lowest value.
Absolute Maximum:
Absolute Minimum:
Step 5