In the last lesson, you saw the computer display values for

`sin`

and `cos`

. The results are always some long decimal number
between -1 and 1. Strange huh? Here's a neat trigonometric identity you may have seen before. If you square the result of a `sin`

and add it to the square of a
`cos`

, you'll always get the same number. Do you know what this number is? Try out this code and see. (Hint: This is an example of the famous identity $\sin(x)^2+\cos(x)^2=1$.
Type your code here:

See your results here:

Does your code work? Want to run it on your iPhone?

Here's your code:

- Use [Control]-[C] (Windows) or [⌘]-[C] (MacOS) to copy your code.
- Paste it using [Control]-[V] (Windows) or [⌘]-[V] (MacOS) into
this page
- Then click the "Use on iPhone" button that you'll see.