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In any ` A B C`, prove that:`2{asin^2C/2+csin^2A/2}=a+c-b` |
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Answer» We know, `2sin^2x = 1-cos2x` `:. L.H.S. = 2(asin^2(C/2)+csin^2(A/2))` `=a(1-cosC)+c(1-cosA)` `=a+c -(acosC+c cosA)` From projection formula, `b = (acosC+c cosA)` `:. a+c -(acosC+c cosA) = a+c - b = R.H.S.` |
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