Question

How do you graph `1/2sin(x-pi)`?

Answer 1

Observing the equation of your function you can deduce a lot of things.
Considering: `y=1/2sin(1*x-pi)` you have a sine curve with:

1]
The `1` in front of `x` (indicated as `k`) allows you to evaluate the length `lambda` of your sine curve; `k=(2pi)/lambda` or `1=(2pi)/lambda` and `lambda=2pi`;

2]
The `1/2` is the Amplitude of your sine curve (maximum height);

3]
`-pi` in the argument of `sin` means that your sine is "moved" starting at a value that is `sin(-pi)` when `x=0`; consequently it will start not "going up" as the normal sine functions but down: