Hi, I'm having a lot of trouble solving the following question related to trig differentiation. I would greatly appreciate any help.

1) Differentiate

Thanks:)

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- May 31st 2010, 08:16 PMspoc21Trigonometric differentiation help!
Hi, I'm having a lot of trouble solving the following question related to trig differentiation. I would greatly appreciate any help.

1) Differentiate

Thanks:)

- May 31st 2010, 08:18 PMnikhil
-2(sinx)tan(cosx)[sec(cosx)]^2

- May 31st 2010, 08:55 PMspoc21
- May 31st 2010, 09:50 PMnikhil
d/dx (tan(cosx))^2

= 2tan(cosx)[d/dx(tan(cosx))]

=2tan(cosx)(sec(cosx))^2(d/dx (cosx))

=2tan(cosx)(sec(cosx))^2(-sinx)

=-2(sinx)tan(cosx)(sec(cosx))^2 - Jun 1st 2010, 12:59 AMHallsofIvy
Nikhil used the chain rule.

Let u= cos(x),[/tex]v= tan(u)[/tex], and

Then , , and

The chain rule says

.

Of course, nikhil did it with specifically writing out "u", "v", and "w".