# Antidfferentiation Of trigonometry functions

• July 6th 2008, 03:47 PM
McCoy
Antidfferentiation Of trigonometry functions
antidifferentiate sin(3x-pi/4) :using a pen and paper, I got (-1/3)cos(3x-pi/4) + c. I also tried it on ti-89 titanium and I got an answer that i think is incorrect.Here is a screen shot: so my question is, can we say the ti 89 answer is also correct?
• July 6th 2008, 04:03 PM
galactus
Yes, you are both correct. Just in different forms.

You should know that $cos(x-\frac{\pi}{4})=sin(x+\frac{\pi}{4})$
• July 6th 2008, 08:04 PM
CaptainBlack
Quote:

Originally Posted by galactus
Yes, you are both correct. Just in different forms.

You should know that $cos(x-\frac{\pi}{4})=sin(x+\frac{\pi}{4})$

Well I would say that the calculator is wrong or rather incomplete as it has dropped the arbitary constant, but this appears to be a common feature of some CAS's

RonL
• July 6th 2008, 08:41 PM
Chris L T521
Quote:

Originally Posted by CaptainBlack
Well I would say that the calculator is wrong or rather incomplete as it has dropped the arbitary constant, but this appears to be a common feature of some CAS's

RonL

You can make the constant appear:

http://img.photobucket.com/albums/v4.../SIN3X-PI4.jpg

--Chris
• July 7th 2008, 03:39 PM
McCoy
I want to thank you all guys for your great contributions.It's much appreciated.