Question

precalc!! help

Answer 1

The sin function oscillates between -1 and 1. So the second term of the function, a*sin(-2x) will oscillate between -a and a. Notice that they're asking you to make the function go between -5 and 15. -5 is 6-9. 15 is 6+9.

Answer 2

so a=? im just a little confused on what the answer is well or how i write it..? thanks for your help

Answer 3

I hate giving answers, so let me giving an example and show you how I would work through it.
Problem:
f(x) = 10 + a*sin(x)
What value of a will make f(x) oscillate between 7 and 13?
Solution:
Notice the difference between 10 and the values they want it to oscillate between.
7 = 10-3 and
13 = 10+3
I know that if sin(x) oscillates between -1 and 1, so if I choose a = 3, then the function will oscillate between:
10 + 3(-1) and
10 + 3(1)
Which becomes
10-3 and
10+3

So a =3 works.