Trig help (1 Viewer)

[Toplad_56]

Hey guys! this question has stumped me for quite a bit, anyone able to provide working out?

solve cos^2x + 7sinxcosx = 3 for for 0 < or equal to x < or equal to 360

 

[kawaiipotato]

The one I'm thinking of right now is to convert the cos^(2)x into 1/2 [cos2x + 1] and then convert 7sinxcosx into 7/2 sin2x (double angle). Then expand and collect al the trigonometric functions to one side and constants on the other. You'll get something like cos2x + 7sin2x = 5
Then transform the LHS into one trigonometric function eg. Rcos (2x-a) and use fundamental formula from there

 

[rand_althor]