Have you tried converting the hyperbolics to exponentials and then simplifying?
Jan 18th 2011, 07:38 PM
No, but the cosh(y) is posing a big problem. I have no idea how to get rid of that, so that I am left with a function which only depends on the variable (x).
Jan 18th 2011, 07:59 PM
Chris L T521
Originally Posted by Mindless
Hello there. I'm new to this forum so I apologise in advance if what I have posted seems a little unclear to you. I just need a little help with the following question.
If, sinhy = (4sinhx - 3) / (4 + 3sinhx)
dy/dx = -5 / (4 + 3sinhx)
My final answer contains coshy, and I do not know where to go from there to get the above.
Thanks in advance.
Note that , as you correctly said.
Now, recall the identity . So in your case
If you get in terms of x, you should be able to get the answer. However, when I did this, I got -- not the negative value you provided.
I hope this helps!
Jan 19th 2011, 10:08 AM
That was really helpful! yes your right Chris, I also end up with a positive value. Maybe some further fiddling around could bring out the negative five, or maybe the book is incorrect? :P. Anyway, thank you very much for your help. Much appreciated.
Jan 19th 2011, 11:38 AM
Originally Posted by Chris L T521
Why is this?
Jan 19th 2011, 11:59 AM
Originally Posted by dwsmith
Why is this?
is an identity for hyperbolic trig functions this gives