# Inverse Trig Function: Find Derivative of the Function

by chapsticks
Tags: derivative, function, inverse, trig
 P: 38 1. The problem statement, all variables and given/known data find the derivative of the function f(x)=arcsec(4x) 2. Relevant equations I think this is a Relevant equations. d/dx[arcsecu]=u'/(|u|(√u2-1) 3. The attempt at a solution f'(x)=4/(|4|(√42-1) =1/√15 I keep getting wrong in my online homework why?
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 Quote by chapsticks 1. The problem statement, all variables and given/known data find the derivative of the function f(x)=arcsec(4x) 2. Relevant equations I think this is a Relevant equations. d/dx[arcsecu]=u'/(|u|(√u2-1) 3. The attempt at a solution f'(x)=4/(|4|(√42-1) =1/√15 I keep getting wrong in my online homework why?
What happened to the x??
 P: 38 is it 4/(|4x|(√4x2-1)) I keep getting it wrong
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## Inverse Trig Function: Find Derivative of the Function

What is u in your original integral? What is $u^2$?
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P: 24,422
 Quote by chapsticks is it 4/(|4x|(√4x2-1)) I keep getting it wrong
That's sort of close. But look up the formula again. Isn't the square root part $\sqrt(u^2-1)$ instead of what you have? And when you write something like 4x^2 it's not clear whether you mean (4x)^2 or 4*(x^2). Which do you mean?
 P: 38 I mean this one (4x)^2
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P: 24,422
 Quote by chapsticks I mean this one (4x)^2
Ok, then keep writing it like that. And what about my other question?
 P: 38 I did this one in my homework online and it keeps saying I'm wrong Attached Thumbnails
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P: 24,422