A point on a curve is said to be an extremum if it is a local minimum ...
The first step to find the extrema of a curve is to find its derivative and then look for the points where the derivative is zero or undefined. So, let's find the derivative of the given curve:
f(x) = 3x^4
f'(x) = 12x^3
Now, we need to find the points where f'(x) is zero or undefined:
12x^3 = 0
x = 0
Since f'(x) is defined for all x, there are no points where it is undefined. Therefore, the only point where f'(x) is zero is x = 0.
To determine whether this point is a local minimum or a local maximum, we need to look at the sign of f''(x) at x = 0:
f''(x) = 36x^2
f''(0) = 0
Since f''(0) = 0, we cannot determine the type of extremum at x = 0 using the second derivative test. Instead, we need to look at the behavior of f(x) near x = 0.
If we look at the graph of f(x) = 3x^4, we can see that it is a even function, which means that it is symmetric about the y-axis. This means that f(x) has a local minimum at x = 0, since the curve approaches 0 from both sides and goes upward.
Therefore, the curve has one local minimum at x = 0, and no local maximums.