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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.

**What are the Double-Angle Identities or Double-Angle Formulas?**

sin(2x) = 2sin(x)cos(x)

cos(2x) = cos^{2}(x) - sin^{2}(x) = 1 - 2sin^{2}(x) = 2cos^{2}(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) = cos^{2}(x) - sin^{2}(x)

How to use the sine and cosine addition formulas to prove the double-angle formulas.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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) = cos

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) = cos

How to use the sine and cosine addition formulas to prove the double-angle formulas.

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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