I would use:

Results 1 to 8 of 8

- November 13th 2012, 05:49 PM #1
## Does this Look right?

Suppose and is

**negative**. Here are some small variations on the previous problems:

Which one of the two addition formals would put me on the right way?

sin(u-pi)=sin(u)cos(pi)-cos(u)sin(pi)

or

sin(-(12/13)-pi)= sin-(12/13)cos(pi)-cos-(12/13)sin(pi)?

- November 13th 2012, 05:58 PM #2

- November 13th 2012, 06:35 PM #3

- November 13th 2012, 06:37 PM #4

- November 13th 2012, 07:17 PM #5

- November 13th 2012, 07:39 PM #6

- November 13th 2012, 07:42 PM #7

- November 13th 2012, 08:15 PM #8