I am given the function y=2 times x^2 + 4
The domain is -3< x <5
I am to find the range.
My book (Sparknotes Math lvl 2 review book) says, "The best way to solve this type of problem is to manipulate the domain of x ine xactly the same way that x is manipulated in the function. First x is squared, then multiplied by 2, then aded to 4; we need to do the same thing to the bounds of the domain" Ok... so then they have this:
4<2x^2 +4 < 54
I don't understand steps 2 and 3. -3 squared is 9. 9 times 2 is 18, plus 4 is 22. I want to sasy there is a typo, but when I graphed it, 4 appeared to be correct (unless I read the graph wrong). Is it a typo or am I missing something ?