Sin/cos are tightly connected to the complex exponential and exhibit a lot of such behavior. In particular, sin(x+it) = sin(x)cosh(y) + i cos(x)sinh(y). Set x

Sin/cos are tightly connected to the complex exponential and exhibit a lot of such behavior. In particular, sin(x+it) = sin(x)cosh(y) + i cos(x)sinh(y). Set x something to zero out cosine, and rely on the exponential nature of cosh to find a target y value.