Trigonometry Examples

Solve for x 2cos(2x)^2-1=sin(4x)
Step 1
Subtract from both sides of the equation.
Step 2
Simplify .
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Step 2.1
Apply the cosine double-angle identity.
Step 2.2
Multiply by .
Step 3
Divide each term in the equation by .
Step 4
Cancel the common factor of .
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Step 4.1
Cancel the common factor.
Step 4.2
Rewrite the expression.
Step 5
Separate fractions.
Step 6
Convert from to .
Step 7
Divide by .
Step 8
Separate fractions.
Step 9
Convert from to .
Step 10
Divide by .
Step 11
Multiply by .
Step 12
Subtract from both sides of the equation.
Step 13
Divide each term in by and simplify.
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Step 13.1
Divide each term in by .
Step 13.2
Simplify the left side.
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Step 13.2.1
Dividing two negative values results in a positive value.
Step 13.2.2
Divide by .
Step 13.3
Simplify the right side.
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Step 13.3.1
Divide by .
Step 14
Take the inverse tangent of both sides of the equation to extract from inside the tangent.
Step 15
Simplify the right side.
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Step 15.1
The exact value of is .
Step 16
Divide each term in by and simplify.
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Step 16.1
Divide each term in by .
Step 16.2
Simplify the left side.
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Step 16.2.1
Cancel the common factor of .
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Step 16.2.1.1
Cancel the common factor.
Step 16.2.1.2
Divide by .
Step 16.3
Simplify the right side.
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Step 16.3.1
Multiply the numerator by the reciprocal of the denominator.
Step 16.3.2
Multiply .
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Step 16.3.2.1
Multiply by .
Step 16.3.2.2
Multiply by .
Step 17
The tangent function is positive in the first and third quadrants. To find the second solution, add the reference angle from to find the solution in the fourth quadrant.
Step 18
Solve for .
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Step 18.1
Simplify.
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Step 18.1.1
To write as a fraction with a common denominator, multiply by .
Step 18.1.2
Combine and .
Step 18.1.3
Combine the numerators over the common denominator.
Step 18.1.4
Add and .
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Step 18.1.4.1
Reorder and .
Step 18.1.4.2
Add and .
Step 18.2
Divide each term in by and simplify.
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Step 18.2.1
Divide each term in by .
Step 18.2.2
Simplify the left side.
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Step 18.2.2.1
Cancel the common factor of .
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Step 18.2.2.1.1
Cancel the common factor.
Step 18.2.2.1.2
Divide by .
Step 18.2.3
Simplify the right side.
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Step 18.2.3.1
Multiply the numerator by the reciprocal of the denominator.
Step 18.2.3.2
Multiply .
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Step 18.2.3.2.1
Multiply by .
Step 18.2.3.2.2
Multiply by .
Step 19
Find the period of .
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Step 19.1
The period of the function can be calculated using .
Step 19.2
Replace with in the formula for period.
Step 19.3
The absolute value is the distance between a number and zero. The distance between and is .
Step 20
The period of the function is so values will repeat every radians in both directions.
, for any integer
Step 21
Consolidate the answers.
, for any integer