Post a New Question

Trig

posted by .

prove sin(α+β)sin(α-β)=cos^2β-cos^2α
please help... this is the only one I
didn't understand out of all my homework...

  • Trig -

    sin(a+b)sin(a-b)
    (sina cosb + cosa sinb)(sinacosb - cosa sinb)
    sin^2acos^2b + sinacosasinbcosb - sinacosasinbcosb - cos^2asin^2b)
    (1-cos^2a)cos^2b - (1-cos^2b)cos^2a
    cos^2b - cos^2acos^2b - cos^2a + cos^2acos^2b
    cos^2b - cos^2a

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

More Related Questions

Post a New Question