Differentiation Watch

RHI11
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#1
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#1
The question is "given that x=sec4y, a) find dy/dx in terms of y, b) show that dy/dx = k/x(sqrt(x^2 - 1))" but I got dy/dx = 4xsqrt(x^2 - 1) and don't really know what I did wrong.
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I'm God
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#2
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What steps did you take?


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Is the answer -4x^2(sqrt(1-(1/x)^2))?
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RHI11
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#3
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(Original post by I'm God)
What steps did you take?


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Is the answer -4x^2(sqrt(1-(1/x)^2))?
No idea what the answer is. I wrote it as 4sec4y*sqrt(sec^2(4y)-1) which gives what I said in the first post you substitute in x for sec4y.
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I'm God
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(Original post by RHI11)
No idea what the answer is. I wrote it as 4sec4y*sqrt(sec^2(4y)-1) which gives what I said in the first post you substitute in x for sec4y.
Oh I see. I did it using quotient rule.
How do you know you are wrong?
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RHI11
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(Original post by I'm God)
Oh I see. I did it using quotient rule.
How do you know you are wrong?
b) show that dy/dx = k/x(sqrt(x^2 - 1))

My answer isn't in that form.
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I'm God
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(Original post by RHI11)
My answer isn't in that form.
When you started, you did dx/dy, so did you flip the fraction to get dy/dx?
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RHI11
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#7
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(Original post by I'm God)
When you started, you did dx/dy, so did you flip the fraction to get dy/dx?
Lol I'm an idiot thanks
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I'm God
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#8
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(Original post by RHI11)
Lol I'm an idiot thanks
It's okay, I got it wrong, so now I need to figure out where
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