I just started learning Trig identities and i've never been so confused in my life! Can someone please explain how to do this?

Prove: cos (A-B) - cos (A+B) = 2sin (A) sin (B)

Thanks.

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- Mar 20th 2010, 12:25 AMTina7906Compound Angle Formula.
I just started learning Trig identities and i've never been so confused in my life! Can someone please explain how to do this?

Prove: cos (A-B) - cos (A+B) = 2sin (A) sin (B)

Thanks. - Mar 20th 2010, 01:40 AMsa-ri-ga-ma
- Mar 20th 2010, 02:03 AMTina7906
Thank you!

I did that at first and that's where i got stuck.

Im not actually sure how to add and make it equal 2sin (A) sin (B).

Would you be able to explain further? - Mar 20th 2010, 04:13 AMsa-ri-ga-ma