If y = x4 – 10 and if x changes from 2 to 1.99, what is the change in y

Given y = x4 – 10


Differentiating on both sides with respect to x, we get



Applying the power rule we get



It is also given that the value of x changes from from 2 to 1.99, so the change in x is


Δx=2-1.99=0.01


So the change in y becomes,



Substituting the corresponding values we get


Δy=4x3×(0.01)


Now at x=2, the change in y becomes


Δyx=2=4(2)3×(0.01)


Δyx=2=4× 8×(0.01)


Δyx=2=0.32


Hence the change in y is 0.32.

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