If the function $j(x)$ is defined only on domain $[-1,2]$, and is defined on this domain by the formula $$j(x) = 2x^2+1,$$ then what is the range of $j(x)$? Express your answer as an interval or as a union of intervals.
The parabola wll turn upward...it has a minimum value on the defined domain of 1
And the max on the defined domain is 2 (2)^2 + 1 = 9
So......the range on the defined domain is [ 1 ,9 ]
Here's the graph : https://www.desmos.com/calculator/apgmaihobm