How do you differentiate y=cos^-1(1-2x^2)y=cos1(12x2)?

2 Answers
Mar 6, 2016

dy/dx = 2/sqrt(1-x^2) dydx=21x2

Explanation:

Using thecolor(blue)" chain rule " chain rule

d/dx[f(g(x)] = f'(g(x)) . g'(x)

and the standard derivative d/dx(cos^-1 x) =( -1)/sqrt(1 - x^2)

rArr dy/dx = (-1)/sqrt(1 - (1-2x^2)^2) d/dx(1-2x^2)

= (4x)/sqrt(1-1 +4x^2 - 4x^4) =( 4x)/sqrt(4x^2(1-x^2))

= (4x)/(2xsqrt(1-x^2))= 2/sqrt(1-x^2)

Mar 6, 2016

d y=(4x)/(1-2x^2)^2 sin^-1(1-2x^2) d x

Explanation:

y=cos u" " y^'=- u^' * sin u
y=cos^-1(1-2x^2)" "y=cos(1/(1-2x^2))
d y=-((0*(1-2x^2)+4x*1)/(1-2x^2)^2)sin(1/(1-2x^2))*d x
d y=(4x)/(1-2x^2)^2 sin^-1(1-2x^2) d x