Calculus Examples

Find the Concavity f(x)=(1- square root of x)/(1+ square root of x)
Step 1
Find the values where the second derivative is equal to .
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Step 1.1
Find the second derivative.
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Step 1.1.1
Find the first derivative.
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Step 1.1.1.1
Apply basic rules of exponents.
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Step 1.1.1.1.1
Use to rewrite as .
Step 1.1.1.1.2
Use to rewrite as .
Step 1.1.1.2
Differentiate using the Quotient Rule which states that is where and .
Step 1.1.1.3
Differentiate.
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Step 1.1.1.3.1
By the Sum Rule, the derivative of with respect to is .
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
Add and .
Step 1.1.1.3.4
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.1.3.5
Differentiate using the Power Rule which states that is where .
Step 1.1.1.4
To write as a fraction with a common denominator, multiply by .
Step 1.1.1.5
Combine and .
Step 1.1.1.6
Combine the numerators over the common denominator.
Step 1.1.1.7
Simplify the numerator.
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Step 1.1.1.7.1
Multiply by .
Step 1.1.1.7.2
Subtract from .
Step 1.1.1.8
Combine fractions.
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Step 1.1.1.8.1
Move the negative in front of the fraction.
Step 1.1.1.8.2
Combine and .
Step 1.1.1.8.3
Move to the denominator using the negative exponent rule .
Step 1.1.1.9
By the Sum Rule, the derivative of with respect to is .
Step 1.1.1.10
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.1.11
Add and .
Step 1.1.1.12
Differentiate using the Power Rule which states that is where .
Step 1.1.1.13
To write as a fraction with a common denominator, multiply by .
Step 1.1.1.14
Combine and .
Step 1.1.1.15
Combine the numerators over the common denominator.
Step 1.1.1.16
Simplify the numerator.
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Step 1.1.1.16.1
Multiply by .
Step 1.1.1.16.2
Subtract from .
Step 1.1.1.17
Move the negative in front of the fraction.
Step 1.1.1.18
Combine and .
Step 1.1.1.19
Move to the denominator using the negative exponent rule .
Step 1.1.1.20
Simplify.
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Step 1.1.1.20.1
Apply the distributive property.
Step 1.1.1.20.2
Apply the distributive property.
Step 1.1.1.20.3
Apply the distributive property.
Step 1.1.1.20.4
Simplify the numerator.
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Step 1.1.1.20.4.1
Simplify each term.
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Step 1.1.1.20.4.1.1
Multiply by .
Step 1.1.1.20.4.1.2
Rewrite using the commutative property of multiplication.
Step 1.1.1.20.4.1.3
Cancel the common factor of .
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Step 1.1.1.20.4.1.3.1
Factor out of .
Step 1.1.1.20.4.1.3.2
Factor out of .
Step 1.1.1.20.4.1.3.3
Cancel the common factor.
Step 1.1.1.20.4.1.3.4
Rewrite the expression.
Step 1.1.1.20.4.1.4
Multiply by .
Step 1.1.1.20.4.1.5
Rewrite as .
Step 1.1.1.20.4.1.6
Cancel the common factor of .
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Step 1.1.1.20.4.1.6.1
Factor out of .
Step 1.1.1.20.4.1.6.2
Factor out of .
Step 1.1.1.20.4.1.6.3
Cancel the common factor.
Step 1.1.1.20.4.1.6.4
Rewrite the expression.
Step 1.1.1.20.4.1.7
Multiply by .
Step 1.1.1.20.4.1.8
Multiply by .
Step 1.1.1.20.4.2
Combine the opposite terms in .
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Step 1.1.1.20.4.2.1
Add and .
Step 1.1.1.20.4.2.2
Add and .
Step 1.1.1.20.4.3
Combine the numerators over the common denominator.
Step 1.1.1.20.4.4
Subtract from .
Step 1.1.1.20.4.5
Factor out of .
Step 1.1.1.20.4.6
Cancel the common factors.
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Step 1.1.1.20.4.6.1
Factor out of .
Step 1.1.1.20.4.6.2
Cancel the common factor.
Step 1.1.1.20.4.6.3
Rewrite the expression.
Step 1.1.1.20.4.7
Move the negative in front of the fraction.
Step 1.1.1.20.5
Combine terms.
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Step 1.1.1.20.5.1
Rewrite as a product.
Step 1.1.1.20.5.2
Multiply by .
Step 1.1.1.20.6
Reorder factors in .
Step 1.1.2
Find the second derivative.
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Step 1.1.2.1
Differentiate using the Product Rule which states that is where and .
Step 1.1.2.2
Rewrite as .
Step 1.1.2.3
Differentiate using the chain rule, which states that is where and .
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Step 1.1.2.3.1
To apply the Chain Rule, set as .
Step 1.1.2.3.2
Differentiate using the Power Rule which states that is where .
Step 1.1.2.3.3
Replace all occurrences of with .
Step 1.1.2.4
Multiply.
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Step 1.1.2.4.1
Multiply by .
Step 1.1.2.4.2
Multiply by .
Step 1.1.2.5
Differentiate using the Product Rule which states that is where and .
Step 1.1.2.6
Differentiate using the chain rule, which states that is where and .
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Step 1.1.2.6.1
To apply the Chain Rule, set as .
Step 1.1.2.6.2
Differentiate using the Power Rule which states that is where .
Step 1.1.2.6.3
Replace all occurrences of with .
Step 1.1.2.7
Differentiate.
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Step 1.1.2.7.1
By the Sum Rule, the derivative of with respect to is .
Step 1.1.2.7.2
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.2.7.3
Add and .
Step 1.1.2.7.4
Differentiate using the Power Rule which states that is where .
Step 1.1.2.8
To write as a fraction with a common denominator, multiply by .
Step 1.1.2.9
Combine and .
Step 1.1.2.10
Combine the numerators over the common denominator.
Step 1.1.2.11
Simplify the numerator.
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Step 1.1.2.11.1
Multiply by .
Step 1.1.2.11.2
Subtract from .
Step 1.1.2.12
Simplify terms.
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Step 1.1.2.12.1
Move the negative in front of the fraction.
Step 1.1.2.12.2
Combine and .
Step 1.1.2.12.3
Combine and .
Step 1.1.2.12.4
Simplify the expression.
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Step 1.1.2.12.4.1
Move to the left of .
Step 1.1.2.12.4.2
Move to the denominator using the negative exponent rule .
Step 1.1.2.12.5
Cancel the common factor.
Step 1.1.2.12.6
Rewrite the expression.
Step 1.1.2.12.7
Combine and .
Step 1.1.2.12.8
Cancel the common factor.
Step 1.1.2.12.9
Simplify.
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Step 1.1.2.12.9.1
Rewrite the expression.
Step 1.1.2.12.9.2
Multiply by .
Step 1.1.2.13
Differentiate using the Power Rule which states that is where .
Step 1.1.2.14
To write as a fraction with a common denominator, multiply by .
Step 1.1.2.15
Combine and .
Step 1.1.2.16
Combine the numerators over the common denominator.
Step 1.1.2.17
Simplify the numerator.
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Step 1.1.2.17.1
Multiply by .
Step 1.1.2.17.2
Subtract from .
Step 1.1.2.18
Simplify terms.
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Step 1.1.2.18.1
Move the negative in front of the fraction.
Step 1.1.2.18.2
Combine and .
Step 1.1.2.18.3
Combine and .
Step 1.1.2.18.4
Simplify.
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Step 1.1.2.18.4.1
Move to the denominator using the negative exponent rule .
Step 1.1.2.18.4.2
Write as a fraction with a common denominator.
Step 1.1.2.18.5
Combine the numerators over the common denominator.
Step 1.1.2.19
Since is constant with respect to , the derivative of with respect to is .
Step 1.1.2.20
Simplify the expression.
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Step 1.1.2.20.1
Multiply by .
Step 1.1.2.20.2
Add and .
Step 1.1.2.21
Simplify.
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Step 1.1.2.21.1
Rewrite the expression using the negative exponent rule .
Step 1.1.2.21.2
Apply the product rule to .
Step 1.1.2.21.3
Combine terms.
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Step 1.1.2.21.3.1
Multiply the exponents in .
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Step 1.1.2.21.3.1.1
Apply the power rule and multiply exponents, .
Step 1.1.2.21.3.1.2
Cancel the common factor of .
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Step 1.1.2.21.3.1.2.1
Cancel the common factor.
Step 1.1.2.21.3.1.2.2
Rewrite the expression.
Step 1.1.2.21.3.2
Simplify.
Step 1.1.2.21.3.3
Multiply the exponents in .
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Step 1.1.2.21.3.3.1
Apply the power rule and multiply exponents, .
Step 1.1.2.21.3.3.2
Multiply by .
Step 1.1.2.21.4
Reorder the factors of .
Step 1.1.2.21.5
Simplify the numerator.
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Step 1.1.2.21.5.1
Rewrite as .
Step 1.1.2.21.5.2
Expand using the FOIL Method.
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Step 1.1.2.21.5.2.1
Apply the distributive property.
Step 1.1.2.21.5.2.2
Apply the distributive property.
Step 1.1.2.21.5.2.3
Apply the distributive property.
Step 1.1.2.21.5.3
Simplify and combine like terms.
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Step 1.1.2.21.5.3.1
Simplify each term.
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Step 1.1.2.21.5.3.1.1
Multiply by .
Step 1.1.2.21.5.3.1.2
Multiply by .
Step 1.1.2.21.5.3.1.3
Multiply by .
Step 1.1.2.21.5.3.1.4
Multiply by by adding the exponents.
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Step 1.1.2.21.5.3.1.4.1
Use the power rule to combine exponents.
Step 1.1.2.21.5.3.1.4.2
Combine the numerators over the common denominator.
Step 1.1.2.21.5.3.1.4.3
Add and .
Step 1.1.2.21.5.3.1.4.4
Divide by .
Step 1.1.2.21.5.3.1.5
Simplify .
Step 1.1.2.21.5.3.2
Add and .
Step 1.1.2.21.5.4
Add and .
Step 1.1.2.21.5.5
Reorder terms.
Step 1.1.2.21.6
To write as a fraction with a common denominator, multiply by .
Step 1.1.2.21.7
Combine and .
Step 1.1.2.21.8
Combine the numerators over the common denominator.
Step 1.1.2.21.9
Simplify the numerator.
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Step 1.1.2.21.9.1
Rewrite using the commutative property of multiplication.
Step 1.1.2.21.9.2
Multiply by by adding the exponents.
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Step 1.1.2.21.9.2.1
Move .
Step 1.1.2.21.9.2.2
Use the power rule to combine exponents.
Step 1.1.2.21.9.2.3
Combine the numerators over the common denominator.
Step 1.1.2.21.9.2.4
Add and .
Step 1.1.2.21.9.2.5
Divide by .
Step 1.1.2.21.9.3
Simplify .
Step 1.1.2.21.9.4
Add and .
Step 1.1.2.21.9.5
Rewrite in a factored form.
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Step 1.1.2.21.9.5.1
Rewrite as .
Step 1.1.2.21.9.5.2
Let . Substitute for all occurrences of .
Step 1.1.2.21.9.5.3
Factor by grouping.
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Step 1.1.2.21.9.5.3.1
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 1.1.2.21.9.5.3.1.1
Factor out of .
Step 1.1.2.21.9.5.3.1.2
Rewrite as plus
Step 1.1.2.21.9.5.3.1.3
Apply the distributive property.
Step 1.1.2.21.9.5.3.1.4
Multiply by .
Step 1.1.2.21.9.5.3.2
Factor out the greatest common factor from each group.
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Step 1.1.2.21.9.5.3.2.1
Group the first two terms and the last two terms.
Step 1.1.2.21.9.5.3.2.2
Factor out the greatest common factor (GCF) from each group.
Step 1.1.2.21.9.5.3.3
Factor the polynomial by factoring out the greatest common factor, .
Step 1.1.2.21.9.5.4
Replace all occurrences of with .
Step 1.1.2.21.10
Combine.
Step 1.1.2.21.11
Multiply by by adding the exponents.
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Step 1.1.2.21.11.1
Move .
Step 1.1.2.21.11.2
Multiply by .
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Step 1.1.2.21.11.2.1
Raise to the power of .
Step 1.1.2.21.11.2.2
Use the power rule to combine exponents.
Step 1.1.2.21.11.3
Write as a fraction with a common denominator.
Step 1.1.2.21.11.4
Combine the numerators over the common denominator.
Step 1.1.2.21.11.5
Add and .
Step 1.1.2.21.12
Multiply by .
Step 1.1.2.21.13
Reorder terms.
Step 1.1.2.21.14
Factor out of .
Step 1.1.2.21.15
Cancel the common factors.
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Step 1.1.2.21.15.1
Factor out of .
Step 1.1.2.21.15.2
Cancel the common factor.
Step 1.1.2.21.15.3
Rewrite the expression.
Step 1.1.3
The second derivative of with respect to is .
Step 1.2
Set the second derivative equal to then solve the equation .
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Step 1.2.1
Set the second derivative equal to .
Step 1.2.2
Set the numerator equal to zero.
Step 1.2.3
Solve the equation for .
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Step 1.2.3.1
Subtract from both sides of the equation.
Step 1.2.3.2
Raise each side of the equation to the power of to eliminate the fractional exponent on the left side.
Step 1.2.3.3
Simplify the exponent.
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Step 1.2.3.3.1
Simplify the left side.
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Step 1.2.3.3.1.1
Simplify .
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Step 1.2.3.3.1.1.1
Apply the product rule to .
Step 1.2.3.3.1.1.2
Raise to the power of .
Step 1.2.3.3.1.1.3
Multiply the exponents in .
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Step 1.2.3.3.1.1.3.1
Apply the power rule and multiply exponents, .
Step 1.2.3.3.1.1.3.2
Cancel the common factor of .
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Step 1.2.3.3.1.1.3.2.1
Cancel the common factor.
Step 1.2.3.3.1.1.3.2.2
Rewrite the expression.
Step 1.2.3.3.1.1.4
Simplify.
Step 1.2.3.3.2
Simplify the right side.
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Step 1.2.3.3.2.1
Raise to the power of .
Step 1.2.3.4
Divide each term in by and simplify.
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Step 1.2.3.4.1
Divide each term in by .
Step 1.2.3.4.2
Simplify the left side.
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Step 1.2.3.4.2.1
Cancel the common factor of .
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Step 1.2.3.4.2.1.1
Cancel the common factor.
Step 1.2.3.4.2.1.2
Divide by .
Step 1.2.4
Exclude the solutions that do not make true.
Step 2
Find the domain of .
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Step 2.1
Set the radicand in greater than or equal to to find where the expression is defined.
Step 2.2
Set the denominator in equal to to find where the expression is undefined.
Step 2.3
Solve for .
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Step 2.3.1
Subtract from both sides of the equation.
Step 2.3.2
To remove the radical on the left side of the equation, square both sides of the equation.
Step 2.3.3
Simplify each side of the equation.
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Step 2.3.3.1
Use to rewrite as .
Step 2.3.3.2
Simplify the left side.
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Step 2.3.3.2.1
Simplify .
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Step 2.3.3.2.1.1
Multiply the exponents in .
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Step 2.3.3.2.1.1.1
Apply the power rule and multiply exponents, .
Step 2.3.3.2.1.1.2
Cancel the common factor of .
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Step 2.3.3.2.1.1.2.1
Cancel the common factor.
Step 2.3.3.2.1.1.2.2
Rewrite the expression.
Step 2.3.3.2.1.2
Simplify.
Step 2.3.3.3
Simplify the right side.
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Step 2.3.3.3.1
Raise to the power of .
Step 2.3.4
Exclude the solutions that do not make true.
Step 2.4
The domain is all values of that make the expression defined.
Interval Notation:
Set-Builder Notation:
Interval Notation:
Set-Builder Notation:
Step 3
Create intervals around the -values where the second derivative is zero or undefined.
Step 4
Substitute any number from the interval into the second derivative and evaluate to determine the concavity.
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Step 4.1
Replace the variable with in the expression.
Step 4.2
Simplify the result.
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Step 4.2.1
Multiply by by adding the exponents.
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Step 4.2.1.1
Multiply by .
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Step 4.2.1.1.1
Raise to the power of .
Step 4.2.1.1.2
Use the power rule to combine exponents.
Step 4.2.1.2
Write as a fraction with a common denominator.
Step 4.2.1.3
Combine the numerators over the common denominator.
Step 4.2.1.4
Add and .
Step 4.2.2
The final answer is .
Step 4.3
The graph is concave up on the interval because is positive.
Concave up on since is positive
Concave up on since is positive
Step 5