How would one go about solving the following equation? 242= 290cos(theta) + 187cos(phi) 0 = 290sin(theta) - 187sin(phi) I have tried squaring both sides of both equations and adding them, and then using cos2x + sin2x = 1 to narrow some stuff down, and basically only found that: phi + theta = 123.9 degrees. But I still feel like I'm stuck. Maybe I'm missing an identity or something, I am terrible with those. Any help would be appreciated.