Question

Prove that
(a-b)^(2)cos^(2)(c)/(2)+(a+b)^(2)sin^(2)(c)/(2)=c^(2)

Answer 1

LHS

(a−b)2cos2(C2)+(a+b)2sin2(C2)

(a2+b2−2ab)cos2(C2)+(a2+b2+2ab)sin2(C2)

(a2+b2)[cos2(C2)+sin2(C2)]−2ab(cos2(C2)−sin2(C2))

a2+b2−2ab(cos2(C2)−sin2(C2))

a2+b2+2ab(sin2(C2)−cos2(C2))

a2+b2−2ab(cosc)

a2+b2−2ab(a2+b2−c22ab)

a2+b2−a2−b2+c2

c2

RHS.

PLS MARK BRAINLIEST

THANK YOU

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