Question

answer this question​

Answer 1

Multiply 6 in first equation i.e

2cos theta +sin theta = 1 .

We get 12cos theta + 6 sin theta = 6

Now let, 7 cos theta + 6 sin theta =K

Eliminate sin theta , and get values of sin theta and cos theta in terms of K

Sintheta=2K-7/5 , costheta=6-K/5

NOW, we know

sin sqaure theta +cos square theta=1

.put values here in terms of K and

then a quadratic equation in K will form

, on solving it we get K=6 or 2.

hence prooved