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है| ( 005 32 + 005 3 - cos 2x =0बे. क ~— N |
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Answer» cos 3x + cos x - cos 2x = 0[cos 3x + cos x ] - cos 2x = 02 cos [(3x + x)/2] .cos [(3x-x)/2] - cos 2x = 02 cos 2x . cos x - cos 2x = 0cos 2x [ 2 cos x - 1 ] = 0cos 2x = 0 or cos x = 1/2 = cosπ/32x = (2n +1 )π/2 or x = 2mπ +-π/3x = (2n + 1 )π/4 or x = 2mπ +-π/3 ; where n , m∈ I |
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