What is the derivative of y=xarcsin(x^2)?
1 Answer
Explanation:
To make the calculations more interesting, I'll assume that you don't know what the derivative of
You can differentiate this function by using implicit differentiation. Start by isolating
y/x = arcsin(x^2)" "color(blue)((1))
This is equivalent to
sin(y/x) = x^2" "color(blue)((2))
Differentiate both sides with respect to
d/dx(sin(y/x)) = d/dx(x^2)
cos(y/x) * ((dy)/dx * 1/x - y/x^2) = 2x
Rearrange this to get
(dy)/dx * cos(y/x) * 1/x - y/x^2 * cos(y/x) = 2x
(dy)/dx * cos(y/x) * 1/x = 2x + y/x^2 * cos(y/x)
(dy)/dx = (2x + y/x^2 * cos(y/x))/(cos(y/x) * 1/x)
(dy)/dx = (2x)/(cos(y/x) * 1/x) + y/x^color(red)(cancel(color(black)(2))) * color(red)(cancel(color(black)(x))) * color(red)(cancel(color(black)(cos(y/x))))/color(red)(cancel(color(black)(cos(y/x))))
(dy)/dx = (2x^2)/cos(y/x) * y/x
Use the trigonometric identity
color(blue)(sin^2x + cos^2x = 1)
To write
cos^2x = 1 - sin^2x
sqrt(cos^2x) = sqrt(1-sin^2x)
cosx = sqrt(1 - sin^2x)
Use this identity and equations
(dy)/dx = (2x^2)/sqrt(1-sin^2(y/x)) + arcsin(x^2)
(dy)/dx = (2x^2)/sqrt(1 - (x^2)^2) + arcsin(x^2)
(dy)/dx = color(green)((2x^2)/sqrt(1-x^4) + arcsin(x^2))