# How do you rewrite #sin40cos15-cos40sin15# as a function of a single angle and then evaluate?

##### 1 Answer

Oct 2, 2016

Please read the following:

#### Explanation:

If you're interested in finding out why, you can watch this clip:

Now, this means that:

You can evaluate sin(30) by drawing a diagram as such:

![https://useruploads.socratic.org/5eLIcgERQ3qlwAdbw6dE_socratic_answer_3.jpg)

And you will discover that: