How do you know a function is increasing?

1 Answer
Mar 9, 2018

It will be increasing when the first derivative is positive.

Explanation:

Take the example of the function f(x) = e^(x^2 - 1)f(x)=ex21.

The first derivative is given by f'(x) = 2xe^(x^2 - 1) (chain rule). We see that the derivative will go from increasing to decreasing or vice versa when f'(x) = 0, or when x= 0.

Whenever you have a positive value of x, the derivative will be positive, therefore the function will be increasing on {x|x> 0, x in RR}.

The graph confirms

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Hopefully this helps!