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Using the first principles, find the derivative of #y=(3-x)/sqrt(2-x)# at x=-2?

1 Answer
Jun 19, 2018

Answer:

there is no derivative at that point: infinity by one side, out of domain by the other side

Explanation:

#y = (3 - x)(2 - x)^(-1/2)#

#y' = (-1) (2 - x)^(-1/2) + (3 - x) (-1/2)(2 - x)^(-3/2)(-1)#

#y' = - 1 / (2 - x)^(1/2) + (3 - x) / (2 * (2 - x)^(3/2))#

#y' = (-2* (2 - x)+ 3 - x) / (2 * (2 - x)* (2 - x)^(1/2))#

#y' = (x - 1) / (2 * (2 - x)* sqrt(2 - x))#