jmc

Question

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.

Accepted Answer

Note that x^2 assumes every value from 0 to 4, inclusive, as x varies throughout the interval [-1,2]. Therefore, j(x) assumes every value from 2(0)+1=1 to 2(4)+1=9 (and no other values). The range of j(x) is [1,9].