First we take the derivative of the function, this gives us dy/dx = cos(x)
Now we work out the different x values for y = 0 and y = 1.
sin(x) = 0 => x = 0, sin(x) = 1 => x = pi/2 (90 degrees)
We then substitute these values into dy/dx which gives us two gradients of 1 and 0 respectively
We can then work out the angle between these two values as the difference between the tangents of the two gradients
(angle = tan(m), this gives us the answer of 45 degrees (angle = tan(1) - tan(0))