Question

Pleasee help mee12sin(x)-5cos(x)=6,5​

Answer 1

We turn -5,12 into polar coordinates.  It's a Pythagorean Triple so

r = 13   Ф=arctan(-12/5) + 180°   ( in the second quadrant )

so -5 = 13 cos Ф, 12 = 13 sin Ф

12 sin x - 5 cos x = 6.5

13 sinФ sin x + 13 cos Ф cos x = 6.5  

13 cos(x - Ф) = 6.5

cos(x - Ф) = 1/2

cos(x - Ф) = cos 60°

x - Ф = ± 60° + 360° k     integer k

x = Ф ± 60° + 360° k  

x = 180° + arctan(-12/5) ± 60° + 360° k  

That's the exact answer;

x ≈  180° - 67.38° ± 60° + 360° k  

x ≈  122.62° ± 60° + 360° k  

x ≈  { 62.62°, 182.62°} + 360° k,  integer k