Question

If cosA+ CosB + CosC=0=sinA+ SinB+SinC then
$\cos {}^{2} ( { \frac{a - b}{2} } )$
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Answer 1

Answer:

If cosA + cosB + cosC = 0 = sinA + sinB + sinC , then value of cos(A−B) + cos(B−C) + cos(C−A) = -3/2

Step-by-step explanation: