Michael M. answered 02/23/21
Math, Chem, Physics, Tutoring with Michael ("800" SAT math)
You would have to use the quotient rule here. The top function is x3-y and the bottom function is 1-y3
From the chain rule the left hand side becomes [ (1-y3) • d/dx(x3-y) - (x3-y) • d/dx(1-y3) ] / (1-y3)2
d/dx (x3 - y) = 3x2 - dy/dx = 3x2 - y'
d/dx (1-y3) = -3y2y'
Now we plug in to get:
[ (1-y3) • (3x2 -y') - (x3-y) • (-3y2y' ) ] / (1-y3)2
The derivative of the right hand side is just 1 so,
[ (1-y3) • (3x2 -y') - (x3-y) • (-3y2y' ) ] / (1-y3)2 = 1
(1-y3) • (3x2 -y') - (x3-y) • (-3y2y' ) = (1-y3)2
Split the first product
(1-y3)(3x2) - (1-y3)y' - (x3-y)(-3y2y' ) = (1-y3)2
Simplify
(1-y3)(3x2) - (1-y3)y' + 3y2(x3-y)y' = (1-y3)2
Put everything multiplied by y' on one side and everything not multiplied by y' on the other
- (1-y3)y' + 3y2(x3-y)y' = (1-y3)2 - (1-y3)(3x2)
Combine the y' terms
y' [ 3y2(x3-y) - (1-y3)] = (1-y3)2 - (1-y3)(3x2)
Solve for y' by dividing
y' = [ (1-y3)2 - (1-y3)(3x2) ] / [ 3y2(x3-y) - (1-y3)]