$f(x)=5\sin(x+0.927)$
It was also written in another form as $3\sin x+4\cos x$.
I understand that for $k$ to have no solutions, the range would be $|k|>5$. But this question confused me, because it asked for specific values rather than a range, and I assume it asks for two solutions for EACH answer of $k$.
Thanks in advance!