Equivalence of two sine arguments

[acherentia]

Homework Statement

Hecht in his optics mentions that Asin(kx-wt+pi) is equivalent to Asin(wt-kx)
w=greek omega

Homework Equations

What is the fundamental reason behind this?

The Attempt at a Solution

I have a hunch it's plain trigonometry applied, but none of the things that I can think of bring up this result.

 

[ideasrule]

Do you know the identity sin(a+b)=sin(a)cos(b)+sin(b)cos(a)?

 

[acherentia]

yes, i do it works that way and thank you very much. I solved it too with a geometrical argument on the trig circle, but i like your approach much better.