Trigonometric functions

[panzerbase]

Can the TI89 simplify trigonometric functions/expressions such as:

cos(x)+cos(x)tan(2x)

I've tried playing around with txpand and tcollect, but no luck.

[mellamokb]

Hi panzerbase,

The TI-89 should be able to simplify your trig expression if it has a readily-available simpler form. Verify that you are in Radian mode (MODE -> angle), as that sometimes makes trig manipulation work better.

What result are you expecting to see from simplifying cos(x) + cos(x)tan(2x)?

Hope this helps!

Regards,
~ mellamokb