(a,b constants)

How do I go about this?

The constant "a" or "b" independent from cos/sin here?..

Is this is correct?

OR this one is the correct one?

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- December 11th 2012, 05:40 AMameerulislamchain rule problem, with 2 constants!
(a,b constants)

How do I go about this?

The constant "a" or "b" independent from cos/sin here?..

Is this is correct?

OR this one is the correct one?

- December 11th 2012, 06:04 AMMarkFLRe: chain rule problem, with 2 constants!
The second one is equivalent to the original statement.

- December 11th 2012, 06:51 AMameerulislamRe: chain rule problem, with 2 constants!
then we have to use the product rule right?

- December 11th 2012, 07:03 AMMarkFLRe: chain rule problem, with 2 constants!
No, you have a sum, not a product. Differentiating term by term, I would use the power and chain rules.

- December 11th 2012, 07:08 AMameerulislamRe: chain rule problem, with 2 constants!
- December 11th 2012, 07:15 AMMarkFLRe: chain rule problem, with 2 constants!
If and are constants, while you could technically use the product rule, I would simply use the rule:

where is an arbitrary constant.

You will get the same result using the product rule since the derivative of a constant is zero. - December 11th 2012, 07:16 AMameerulislamRe: chain rule problem, with 2 constants!
I solved the problem but my result is differing from the text book..

I got

The text book has

an extra between 2a and 2b. - December 11th 2012, 07:19 AMMarkFLRe: chain rule problem, with 2 constants!
You have only partially applied the chain rule. You must also apply it to the arguments of the trig. functions. This is where the comes from that you are missing.

- December 11th 2012, 07:55 AMameerulislamRe: chain rule problem, with 2 constants!
this is what I did

then

I should have to applied product rule here? or maybe rewrite to

is that is my mistake? - December 11th 2012, 08:05 AMMarkFLRe: chain rule problem, with 2 constants!
You need in the case from your previous post:

- December 11th 2012, 09:16 AMameerulislamRe: chain rule problem, with 2 constants!
- December 11th 2012, 09:39 AMMarkFLRe: chain rule problem, with 2 constants!
A trig. function of a constant is just a constant, so its derivative would be zero.

How deeply you must go is determined by how many "compositions" you have.

The two terms you began with have 3 compositions each. Let's look at the first term:

If we let:

then we may state:

The chain rule tells us then: