# Unexpected result for trigonometric function

I'm trying to solve the following trig eqn using sage.

$$sin(x)-cos(x) = 0$$

Hand calculation give me the result of: $$x=\frac{\pi}{4} + n\pi$$

However, the `solve()`

function gives me a different result, why is that?:

```
sage:
sage: solve(sin(x)-cos(x) == 0, x, to_poly_solve=True)
[x == 1/4*pi + pi*z25]
sage:
```

Also, what's `z`

in the answer? I haven't defined any such variable.