Question
Wed June 08, 2011 By: Ayush Sagar

prove that

Expert Reply
Wed June 08, 2011
sinA + sinB = 2 sin (A + B)/2 cos (A-B)/2
cosA + cosB = 2 cos(A+B)/2 cos(A-B)/2

(sinA+sin B)/(cosA+cosB)={sin(A+B)/2}/{cos(A+B)/2}
(sinA+sin B)/(cosA+cosB)=tan(A+B)/2
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