Friday

December 19, 2014

December 19, 2014

Posted by **-** on Sunday, November 8, 2009 at 10:29am.

2sinxsiny = cos(x-y) - cos(x+y)

- advanced functions -
**drwls**, Sunday, November 8, 2009 at 10:59amRewrite the right side, using

cos (x + y) = cos x cos y - sin x sin y

cos (x - y) = cos x cos y + sin x sin y

You should be familiar with those two identities.

- advanced functions -
**nando**, Wednesday, October 15, 2014 at 6:53pmkagr

**Answer this Question**

**Related Questions**

advanced functions - Prove that 2sinxsiny = cos(x-y) - cos(x+y) Prove that sin2x...

Advanced Functions/Trig - Prove the following: sin(x+y)sin(x-y) = cos^2 (y) - ...

Trigonometry - Write equivalent equations in the form of inverse functions for a...

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

Trigonometry desperate help, clueless girl here - 2. solve cos 2x-3sin x cos 2x...

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

MATH - Hi, I really need help with these questions. I did some of them halfway, ...

Advanced Functions/Trig - Prove the identity: cos^4 x + sin^4 x = 1 - (1/2)sin^2...

Math - Prove each identity: a) 1-cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x-1 = sin...

Trigonometry - 1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two ...