Question

if cos(ɑ + β) = 0 , then sin (ɑ - β) can be reduced to

• A. cos β
• B. cos 2β
• C. sin ɑ
• D. sin 2ɑ

Answer 1

Answer:

B. cos 2β

cos (ɑ+β) = cos 90 ɑ+β = 90 ɑ = 90- β sin (ɑ - β) = sin (90 - β - β) = sin (90 - 2β) = cos (2β) sin (90-x)=cosx