Wednesday

October 22, 2014

October 22, 2014

Posted by **Hannah** on Saturday, February 27, 2010 at 10:38pm.

cos^2 B - sin^2 B = 2 cos^2 B -1

I know that cos^2 B - sin^2 B = 2 cos^2 B -1 by the double angle formula but I do not know how to show this.

- Pre-Cal -
**Reiny**, Saturday, February 27, 2010 at 10:41pmLS =

cos^2 B - sin^2 B

= cos^2 B - (1 - cos^2 B)

= 2cos^2 B - 1

= RS

**Answer this Question**

**Related Questions**

Math - Calculus - The identity below is significant because it relates 3 ...

pre-cal - Simplify the given expression........? (2sin2x)(cos6x) sin 2x and cos ...

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

tigonometry - expres the following as sums and differences of sines or cosines ...

Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...

trig - it says to verify the following identity, working only on one side: cotx+...

algebra - Can someone please help me do this problem? That would be great! ...

trig - Reduce the following to the sine or cosine of one angle: (i) sin145*cos75...

trigonometry - Verify that following are identities: 1. cos 3t = 4 cosł t-3 cos ...

calculus - Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x...