Trigonometry Examples

Find the Exact Value (2tan(pi/8))/(1-tan(pi/8)^2)
Step 1
The exact value of is .
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Step 1.1
Rewrite as an angle where the values of the six trigonometric functions are known divided by .
Step 1.2
Apply the tangent half-angle identity.
Step 1.3
Change the to because tangent is positive in the first quadrant.
Step 1.4
Simplify .
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Step 1.4.1
The exact value of is .
Step 1.4.2
Write as a fraction with a common denominator.
Step 1.4.3
Combine the numerators over the common denominator.
Step 1.4.4
The exact value of is .
Step 1.4.5
Write as a fraction with a common denominator.
Step 1.4.6
Combine the numerators over the common denominator.
Step 1.4.7
Multiply the numerator by the reciprocal of the denominator.
Step 1.4.8
Cancel the common factor of .
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Step 1.4.8.1
Cancel the common factor.
Step 1.4.8.2
Rewrite the expression.
Step 1.4.9
Multiply by .
Step 1.4.10
Multiply by .
Step 1.4.11
Expand the denominator using the FOIL method.
Step 1.4.12
Simplify.
Step 1.4.13
Apply the distributive property.
Step 1.4.14
Cancel the common factor of .
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Step 1.4.14.1
Cancel the common factor.
Step 1.4.14.2
Rewrite the expression.
Step 1.4.15
Combine and .
Step 1.4.16
Simplify each term.
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Step 1.4.16.1
Apply the distributive property.
Step 1.4.16.2
Multiply .
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Step 1.4.16.2.1
Raise to the power of .
Step 1.4.16.2.2
Raise to the power of .
Step 1.4.16.2.3
Use the power rule to combine exponents.
Step 1.4.16.2.4
Add and .
Step 1.4.16.3
Simplify each term.
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Step 1.4.16.3.1
Rewrite as .
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Step 1.4.16.3.1.1
Use to rewrite as .
Step 1.4.16.3.1.2
Apply the power rule and multiply exponents, .
Step 1.4.16.3.1.3
Combine and .
Step 1.4.16.3.1.4
Cancel the common factor of .
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Step 1.4.16.3.1.4.1
Cancel the common factor.
Step 1.4.16.3.1.4.2
Rewrite the expression.
Step 1.4.16.3.1.5
Evaluate the exponent.
Step 1.4.16.3.2
Multiply by .
Step 1.4.16.4
Cancel the common factor of and .
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Step 1.4.16.4.1
Factor out of .
Step 1.4.16.4.2
Factor out of .
Step 1.4.16.4.3
Factor out of .
Step 1.4.16.4.4
Cancel the common factors.
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Step 1.4.16.4.4.1
Factor out of .
Step 1.4.16.4.4.2
Cancel the common factor.
Step 1.4.16.4.4.3
Rewrite the expression.
Step 1.4.16.4.4.4
Divide by .
Step 1.4.16.5
Apply the distributive property.
Step 1.4.16.6
Multiply by .
Step 1.4.17
Add and .
Step 1.4.18
Subtract from .
Step 2
Simplify the denominator.
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Step 2.1
Rewrite as .
Step 2.2
Since both terms are perfect squares, factor using the difference of squares formula, where and .
Step 2.3
Simplify.
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Step 2.3.1
The exact value of is .
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Step 2.3.1.1
Rewrite as an angle where the values of the six trigonometric functions are known divided by .
Step 2.3.1.2
Apply the tangent half-angle identity.
Step 2.3.1.3
Change the to because tangent is positive in the first quadrant.
Step 2.3.1.4
Simplify .
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Step 2.3.1.4.1
The exact value of is .
Step 2.3.1.4.2
Write as a fraction with a common denominator.
Step 2.3.1.4.3
Combine the numerators over the common denominator.
Step 2.3.1.4.4
The exact value of is .
Step 2.3.1.4.5
Write as a fraction with a common denominator.
Step 2.3.1.4.6
Combine the numerators over the common denominator.
Step 2.3.1.4.7
Multiply the numerator by the reciprocal of the denominator.
Step 2.3.1.4.8
Cancel the common factor of .
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Step 2.3.1.4.8.1
Cancel the common factor.
Step 2.3.1.4.8.2
Rewrite the expression.
Step 2.3.1.4.9
Multiply by .
Step 2.3.1.4.10
Multiply by .
Step 2.3.1.4.11
Expand the denominator using the FOIL method.
Step 2.3.1.4.12
Simplify.
Step 2.3.1.4.13
Apply the distributive property.
Step 2.3.1.4.14
Cancel the common factor of .
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Step 2.3.1.4.14.1
Cancel the common factor.
Step 2.3.1.4.14.2
Rewrite the expression.
Step 2.3.1.4.15
Combine and .
Step 2.3.1.4.16
Simplify each term.
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Step 2.3.1.4.16.1
Apply the distributive property.
Step 2.3.1.4.16.2
Multiply .
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Step 2.3.1.4.16.2.1
Raise to the power of .
Step 2.3.1.4.16.2.2
Raise to the power of .
Step 2.3.1.4.16.2.3
Use the power rule to combine exponents.
Step 2.3.1.4.16.2.4
Add and .
Step 2.3.1.4.16.3
Simplify each term.
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Step 2.3.1.4.16.3.1
Rewrite as .
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Step 2.3.1.4.16.3.1.1
Use to rewrite as .
Step 2.3.1.4.16.3.1.2
Apply the power rule and multiply exponents, .
Step 2.3.1.4.16.3.1.3
Combine and .
Step 2.3.1.4.16.3.1.4
Cancel the common factor of .
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Step 2.3.1.4.16.3.1.4.1
Cancel the common factor.
Step 2.3.1.4.16.3.1.4.2
Rewrite the expression.
Step 2.3.1.4.16.3.1.5
Evaluate the exponent.
Step 2.3.1.4.16.3.2
Multiply by .
Step 2.3.1.4.16.4
Cancel the common factor of and .
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Step 2.3.1.4.16.4.1
Factor out of .
Step 2.3.1.4.16.4.2
Factor out of .
Step 2.3.1.4.16.4.3
Factor out of .
Step 2.3.1.4.16.4.4
Cancel the common factors.
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Step 2.3.1.4.16.4.4.1
Factor out of .
Step 2.3.1.4.16.4.4.2
Cancel the common factor.
Step 2.3.1.4.16.4.4.3
Rewrite the expression.
Step 2.3.1.4.16.4.4.4
Divide by .
Step 2.3.1.4.16.5
Apply the distributive property.
Step 2.3.1.4.16.6
Multiply by .
Step 2.3.1.4.17
Add and .
Step 2.3.1.4.18
Subtract from .
Step 2.3.2
The exact value of is .
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Step 2.3.2.1
Rewrite as an angle where the values of the six trigonometric functions are known divided by .
Step 2.3.2.2
Apply the tangent half-angle identity.
Step 2.3.2.3
Change the to because tangent is positive in the first quadrant.
Step 2.3.2.4
Simplify .
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Step 2.3.2.4.1
The exact value of is .
Step 2.3.2.4.2
Write as a fraction with a common denominator.
Step 2.3.2.4.3
Combine the numerators over the common denominator.
Step 2.3.2.4.4
The exact value of is .
Step 2.3.2.4.5
Write as a fraction with a common denominator.
Step 2.3.2.4.6
Combine the numerators over the common denominator.
Step 2.3.2.4.7
Multiply the numerator by the reciprocal of the denominator.
Step 2.3.2.4.8
Cancel the common factor of .
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Step 2.3.2.4.8.1
Cancel the common factor.
Step 2.3.2.4.8.2
Rewrite the expression.
Step 2.3.2.4.9
Multiply by .
Step 2.3.2.4.10
Multiply by .
Step 2.3.2.4.11
Expand the denominator using the FOIL method.
Step 2.3.2.4.12
Simplify.
Step 2.3.2.4.13
Apply the distributive property.
Step 2.3.2.4.14
Cancel the common factor of .
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Step 2.3.2.4.14.1
Cancel the common factor.
Step 2.3.2.4.14.2
Rewrite the expression.
Step 2.3.2.4.15
Combine and .
Step 2.3.2.4.16
Simplify each term.
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Step 2.3.2.4.16.1
Apply the distributive property.
Step 2.3.2.4.16.2
Multiply .
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Step 2.3.2.4.16.2.1
Raise to the power of .
Step 2.3.2.4.16.2.2
Raise to the power of .
Step 2.3.2.4.16.2.3
Use the power rule to combine exponents.
Step 2.3.2.4.16.2.4
Add and .
Step 2.3.2.4.16.3
Simplify each term.
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Step 2.3.2.4.16.3.1
Rewrite as .
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Step 2.3.2.4.16.3.1.1
Use to rewrite as .
Step 2.3.2.4.16.3.1.2
Apply the power rule and multiply exponents, .
Step 2.3.2.4.16.3.1.3
Combine and .
Step 2.3.2.4.16.3.1.4
Cancel the common factor of .
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Step 2.3.2.4.16.3.1.4.1
Cancel the common factor.
Step 2.3.2.4.16.3.1.4.2
Rewrite the expression.
Step 2.3.2.4.16.3.1.5
Evaluate the exponent.
Step 2.3.2.4.16.3.2
Multiply by .
Step 2.3.2.4.16.4
Cancel the common factor of and .
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Step 2.3.2.4.16.4.1
Factor out of .
Step 2.3.2.4.16.4.2
Factor out of .
Step 2.3.2.4.16.4.3
Factor out of .
Step 2.3.2.4.16.4.4
Cancel the common factors.
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Step 2.3.2.4.16.4.4.1
Factor out of .
Step 2.3.2.4.16.4.4.2
Cancel the common factor.
Step 2.3.2.4.16.4.4.3
Rewrite the expression.
Step 2.3.2.4.16.4.4.4
Divide by .
Step 2.3.2.4.16.5
Apply the distributive property.
Step 2.3.2.4.16.6
Multiply by .
Step 2.3.2.4.17
Add and .
Step 2.3.2.4.18
Subtract from .
Step 3
Expand using the FOIL Method.
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Step 3.1
Apply the distributive property.
Step 3.2
Apply the distributive property.
Step 3.3
Apply the distributive property.
Step 4
Simplify and combine like terms.
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Step 4.1
Simplify each term.
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Step 4.1.1
Multiply by .
Step 4.1.2
Multiply by .
Step 4.1.3
Multiply by .
Step 4.1.4
Multiply .
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Step 4.1.4.1
Raise to the power of .
Step 4.1.4.2
Raise to the power of .
Step 4.1.4.3
Use the power rule to combine exponents.
Step 4.1.4.4
Add and .
Step 4.1.5
Rewrite as .
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Step 4.1.5.1
Use to rewrite as .
Step 4.1.5.2
Apply the power rule and multiply exponents, .
Step 4.1.5.3
Combine and .
Step 4.1.5.4
Cancel the common factor of .
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Step 4.1.5.4.1
Cancel the common factor.
Step 4.1.5.4.2
Rewrite the expression.
Step 4.1.5.5
Simplify.
Step 4.1.6
Apply the distributive property.
Step 4.1.7
Multiply by .
Step 4.1.8
Multiply by .
Step 4.2
Subtract from .
Step 4.3
Add and .
Step 4.4
Add and .
Step 5
Cancel the common factor of and .
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Step 5.1
Factor out of .
Step 5.2
Cancel the common factors.
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Step 5.2.1
Factor out of .
Step 5.2.2
Factor out of .
Step 5.2.3
Factor out of .
Step 5.2.4
Cancel the common factor.
Step 5.2.5
Rewrite the expression.
Step 6
Multiply by .
Step 7
Simplify terms.
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Step 7.1
Multiply by .
Step 7.2
Expand the denominator using the FOIL method.
Step 7.3
Simplify.
Step 7.4
Simplify the expression.
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Step 7.4.1
Move the negative one from the denominator of .
Step 7.4.2
Rewrite as .
Step 7.5
Apply the distributive property.
Step 7.6
Move to the left of .
Step 7.7
Combine using the product rule for radicals.
Step 8
Rewrite as .
Step 9
Apply the distributive property.
Step 10
Multiply .
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Step 10.1
Multiply by .
Step 10.2
Multiply by .
Step 11
Multiply .
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Step 11.1
Multiply by .
Step 11.2
Multiply by .
Step 12
The result can be shown in multiple forms.
Exact Form:
Decimal Form: