#1

I'm trying to find the derivative of this:

y= cot(cos(x))^2

what im getting is:

y'= -csc(cos(x))^4 * 2cos(x) * -sin(x)

but thats not working.

any ideas here?

y= cot(cos(x))^2

what im getting is:

y'= -csc(cos(x))^4 * 2cos(x) * -sin(x)

but thats not working.

any ideas here?

#2

Can somebody post that picture with the bunny that has a pancake on his head

Serious Reply: Try another calculator and compare results?

Serious Reply: Try another calculator and compare results?

*Last edited by Jesus=ConArtist at Feb 24, 2009,*

#3

#4

Thanks

#5

Last math thread I helped in got closed...

#6

first and foremost

do you mean

y= cot^2(cosx)

or

y= cot(cos^2 (x))

the derivative of the first needs power rule, trig rules, and chain rule

in the first form it can be rewritten as

y=cot(cos(x))cot(cosx) then do chain rule and product rule, you should get it eventually, then again I might be wrong.

do you mean

y= cot^2(cosx)

or

y= cot(cos^2 (x))

the derivative of the first needs power rule, trig rules, and chain rule

in the first form it can be rewritten as

y=cot(cos(x))cot(cosx) then do chain rule and product rule, you should get it eventually, then again I might be wrong.

#7

to clarify its

y=cot(cos^2(x))

y=cot(cos^2(x))

#8

I'm getting 2(cot(cosx))(sinx)(csc(cosx))

Assuming that it's cotangent squared of cosine x.

EDIT: You bitch!

In that case, I think it's 2(csc^2(cosx))(cosx)(sinx)

Assuming that it's cotangent squared of cosine x.

EDIT: You bitch!

In that case, I think it's 2(csc^2(cosx))(cosx)(sinx)

*Last edited by abcdboy at Feb 24, 2009,*

#9

i think its y'=-csc^2[2(cosx)(-sinx)]... the derivative of cotx is (-cscx)^2, so its that of 2 (b/c thats the power) times the term in the parentheses (down a power) times the derivative of the term in the parentheses. thereyago.

#10

i think what you got is the same thing except the 2cosxsinx is inside becuase its what you get with the chain rule

#11

In that case, I think it's 2(csc^2(cosx))(cosx)(sinx)

your first 'cos x' should be '(cos x)^2.'

just to make it a bit clearer to the OP, it's chain rule inside a chain rule. first differentiate cot y [where y=cos^2(x)] to get -cosec^2(y) but then you need to differentiate y as well, as dictated by the chain rule.

y is technically a function of a function too, albeit a rather trivial one. the derivative of (cos x)^2 = 2(cos x) . -sin x, which you need to multiply by your -cosec^2 malarky. the minuses cancel and there you go.

*Last edited by Sol9989 at Feb 24, 2009,*