Question

Question #74b80

Answer 1

`(2a+3b)^2+(2b-a)^2=49`, or,

`5a^2+8ab+13b^2=49`..

Explanation:

I will not give the complete Soln., but, will outline of the Soln.

Given, `a=2cosx-3sinx, 7, b=cosx+2sinx`

Solve these eqns. for `cosx, and, sinx` in terms of `a and b`.

Then, use the Identity `: cos^2x+sin^2x=1`, and the Result will be there!.
Enjoy Maths.!