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aitdes6fnistantancos α + cos β1 + cos α cos β2, prove that one of the values of tan31. If cos1stan _ tan2 |
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Answer» cos x=(cosA-cosB)/(1-cosAcosB)cos x=[1-tan^2(x/2)]/[1+tan^2(x/2)]by componendo-dividendo on LHS andRHS[(-1)/tan^2(x/2)]=[(cosA-cosB+1-cosAcosB)/(cosA-cosB-1+c...factorising numerator and denominator of RHS[(-1)/tan^2(x/2)]=[{(1+cosA)(1-cosB)}/{(cosA-1)(1+cosB)}...[{cos^2(A/2)sin^2(B/2)}/{-sin^2(A/2)co...{-cot^2(a/2)tan^2(B/2)} |
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