This problem was pretty tough for me:
can you show me how to do this? Thanks!
Recall thatOriginally Posted by aussiekid90
This is a quadratic. Let y = cos(x):
Using the quadratic formula I get:
Now. so we need to take the positive sign. As it happens the result doesn't seem to have a nice form, so:
. Since this angle is second quadrant, we also get an angle .