Double Angle Identities
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More Lessons for PreCalculus
Math Worksheets
Examples, solutions, videos, worksheets, games and activities to help PreCalculus students learn about the double angle identities.
The following diagram gives the Double-Angle Identities. Scroll down the page for more examples and solutions.
sin(2x) = 2sin(x)cos(x)
cos(2x) = cos2(x) - sin2(x) = 1 - 2sin2(x) = 2cos2(x) - 1
How to use the Double-Angle Identities or Double-Angle Formulas?
Double-Angle Formulas
A few examples that use double-angle formulas from trigonometry.
Using Double Angle Identities to Solve Equations
How to proof the Double-Angle Identities or Double-Angle Formulas?
Double Angle Formulas :
The double angles sin(2x) and cos(2x) can be rewritten as sin(x + x) and cos(x + x).
Applying the cosine and sine addition formulas, we find that sin(2x) = 2sin(x)cos(x).
Also, cos(2x) = cos2(x) - sin2(x)
How to use the sine and cosine addition formulas to prove the double-angle formulas.
More Lessons for PreCalculus
Math Worksheets
Examples, solutions, videos, worksheets, games and activities to help PreCalculus students learn about the double angle identities.
The following diagram gives the Double-Angle Identities. Scroll down the page for more examples and solutions.
sin(2x) = 2sin(x)cos(x)
cos(2x) = cos2(x) - sin2(x) = 1 - 2sin2(x) = 2cos2(x) - 1
How to use the Double-Angle Identities or Double-Angle Formulas?
Double-Angle Formulas
A few examples that use double-angle formulas from trigonometry.
Double Angle Formulas :
The double angles sin(2x) and cos(2x) can be rewritten as sin(x + x) and cos(x + x).
Applying the cosine and sine addition formulas, we find that sin(2x) = 2sin(x)cos(x).
Also, cos(2x) = cos2(x) - sin2(x)
How to use the sine and cosine addition formulas to prove the double-angle formulas.
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