Question

JULI Find the value of sin 50+ sin" 10. If a sin + b cos 0 = c, then prove that a cos 0 -b sin O= v ton AL SECA.

11th - 12th Class

Maths

Solution

143

4.0 (1 ratings)

( a cos theta-b sin theta=c ) Squaring both sides ( a^{2} cos ^{2} theta+b^{2} sin ^{2} theta-2 a b sin theta cos theta ) ( =c^{2} ) ( a^{2}left(1-sin ^{2} thetaright)+b^{2}left(1-cos ^{2} thetaright)-2 a b sin theta ) ( a^{2}-a^{2} sin ^{2} theta+b^{2}-b^{2} cos ^{2} theta-2 a b sin theta ) ( cos theta=c^{2} ) ( frac{7}{a} sin ^{2} theta+b^{2} cos ^{2} theta+2 a b sin theta cos ^{2}={ }^{2}=b^{2}-c^{2} ) ( (a sin theta+b cos theta)^{2}=a^{2}+b^{2}-c^{2} ) ( Rightarrow a sin theta+b cos theta=sqrt{a^{2}+b^{2}-c^{2}} )