Question

Without using the unit circle, how would I know what angle `tanx-1=0` represents?

Answer 1

Adding `1` to both sides leads to the equation: `tanx=1`. We are looking for the angle whose tan is 1. We can rewrite as `x=tan^-1(1)`. A calculator could solve this, or you could simply remember that `tan^-1(1)=\pi/4` radians or `45^o`.