Question

if cos(a+b) =0 than sin(a-b) can be reduced to​

Answer 1

Answer:

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Step-by-step explanation:

cos(a+b)=0 is equivalent to a+b=(2k+1) pi/2 thus b=-a+(2k+1) pi/2, k is an integer.

Then sin(a-b)=sin(2a-(2k+1) pi/2)=sin(2a-k pi-pi/2)=-sin(pi/2-(2a-k pi))=-cos(2a-k pi)

= -cos(2a) if k is even ; cos(2a)