CBSE Class 11-science Answered

Dear Student,

The solution to your problem is as follows:

6cosα + 8sinα = 9

=> (6cosα)² = (9 - 8sinα )²

=> 36cos²α = 81 + 64sin²α - 144sinα

=>36(1-sin²α) = 81 + 64sin²α - 144sinα

=> 81 - 36 + 64sin²α + 36sin²α - 144sinα = 0

=> 100sin²α - 144sinα + 45 = 0

This is a quadratic eqn in sinα, solving it by D-method, we get the two solutions as

=> sinα = 0.9815 ,  0.4585

=> x = 78.962 , y = 27.288

Hence,

sin(x+y) = sin (78.962 + 27.288) = sin (106.25) = 0.96005

Regards Topperlearning.