How to find the derivative of sqrt(4-x^2)?

Method 1
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f (x) = ( 4 - x ² )^(1/2)
f ` (x) = (1/2) ( 4 - x ² )^(-1/2) (-2x)
f ` (x) = - x / ( 4 - x ² )^1/2)

Method 2
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y = u^(1/2) where u = 4 - x ²

dy/du = (1/2) u^(-1/2) and du/dx = - 2x

dy/dx = (1/2) u^(-1/2) [ - 2x ]

dy/dx = - x / u^(1/2)

dy/dx= - x / ( 4 - x ² )^(1/2)

y = √(4 - x^2)
y = (4 - x^2)^1/2
dy/dx = 1/2(4 - x^2)^ -1/2 d/dx -2x
............x
= - -------------------- answer//
.......√(4 - x^2)

y=sqrt(4-x^2)
dy/dx=1/2*(4+x^2)^-1/2*2x
=x/sqrt(4-x^2)