How to determine, when the first and second derivatives of f(x) is positive, negative, or zero.
Printable View
How to determine, when the first and second derivatives of f(x) is positive, negative, or zero.
When f(x) is increasing, f ' (x) will be positive
When f(x) is decreasing, f ' (x) will be negative
When f(x) is concave down, f '' (x) will be negative
When f(x) is concave up, f '' (x) will be positive
When f(x) changed from increasing to decreasing (or vice versa) f ' (x) = 0
When f(x) changes in concavity, f '' (x)= 0
If it helps you, graph all three on the same graph and look at what changes.