Integral of cos^2(x) using the Half Angle Formula

PLEASE NOTE: There is a mistake in this video. The integral of cos(2x) is NOT negative, it is positive sin(2x)/2. I created annotations to show and correct this mistake. Please turn annotations "on" in your YouTube player settings to see them. Thanks.

In this video, we find the integral (or anti-derivative) of cos^2(x). Trigonometric identities are very powerful when it comes to performing integrals. Here, we used the half angle formula (also known as the power reducing formula) to express cos^2(x) as (1 + cos(2x))/2, making this an easy integral to perform.

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Please also watch the video on the Integral of sin^2(x) here - Integral of sin^2(x) using the Half A...

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