LHS=cos276+cos216−cos76cos16
=1/2(2cos²76+2cos²16−2cos76cos16)
=1/2(1+cos152+1+cos32−cos(76+16)⋅cos(76−16))=1/2(2+2cos[(152+32)/2]cos[(152-32)/2]-cos(76+16)−cos(76−16))
=1/2(2+2cos92cos60−cos92−cos60)
=1/2(2+2cos92×1/2−cos92−1/2)
=1/2(2−1/2)
=1/2*3/2=3/4
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LHS=cos276+cos216−cos76cos16
=1/2(2cos²76+2cos²16−2cos76cos16)
=1/2(1+cos152+1+cos32−cos(76+16)⋅cos(76−16))
=1/2(2+2cos[(152+32)/2]cos[(152-32)/2]-cos(76+16)−cos(76−16))
=1/2(2+2cos92cos60−cos92−cos60)
=1/2(2+2cos92×1/2−cos92−1/2)
=1/2(2−1/2)
=1/2*3/2=3/4
Please mark the answer as brainliest