stupid derivative question (1 Viewer)

[fashionista]

hey!!
i have this one derivative question, which, no matter how many times i try i don't get the right answer. Here goes:

if y=x.inversecos(2x)- 1/2.sqrt(1-4x^2) find dy/dx

please help i keep getting

[-2x/sqrt(1/4x^2)] [inversecos(2x)-1]

 

[jonjon]

hey for some reason i got inversecos(2x) as my answer. other stuff cancels out..

 

[shazzam]

err...just wondering how you could DIFFERENTIATE s/th to get an inverse function...? v confused please help

 

[CrashOveride]

err...just wondering how you could DIFFERENTIATE s/th to get an inverse function...? v confused please help

Due to the product rule when differentiating.

jonjon hey for some reason i got inversecos(2x) as my answer. other stuff cancels out..

I also get dy/dx = arccos(2x)