Prove that- c-b cosA-b - c cos A - cosB- cos C

c=acos B+bcos A,b=acos C+ccos A LHS=c bcos Ab c cos A=acos Bacos C=cos Bcos C=RHS ...

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Standard IX

Mathematics

Use of Trigonometric Table

Prove that, ...

Question

Prove that, $\frac{c - b c o s A}{b - c c o s A} = \frac{c o s B}{c o s C}$

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Solution

$c = a cos B + b cos A, b = a cos C + c cos A$
$L H S = \frac{c - b cos A}{b - c cos A} = \frac{a cos B}{a cos C} = \frac{cos B}{cos C} = R H S$

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Prove that, c−b cosAb−c cosA= cosB cosC

c=acosB+bcosA,b=acosC+ccosALHS=c−bcosAb−ccosA=acosBacosC=cosBcosC=RHS

Prove that, $\frac{c - b c o s A}{b - c c o s A} = \frac{c o s B}{c o s C}$

$c = a cos B + b cos A, b = a cos C + c cos A$
$L H S = \frac{c - b cos A}{b - c cos A} = \frac{a cos B}{a cos C} = \frac{cos B}{cos C} = R H S$