- #1
SolCon
- 33
- 1
Hi. :)
Alright, another functions related problem. This question came in 3 parts. I've done the first one but the other 2 are being a problem. Here it is:
Q. The function f is such that f(x) = 2 sin^2(x) − 3 cos^2(x) for 0 ≤ x ≤ p.
(i) Express f(x) in the form a + b cos^2(x), stating the values of a and b.
This was done easily. Answer came as 2-5cos^2(x) + 1 =0, where a=2, b=-5.
(ii) State the greatest and least values of f(x).
I think we have to make a graph of the function here. Problem is, there's cos^2 instead of just cos. I'm not sure how to do this. If there is some other way to find the problem, I'd like to try that too.
(iii) Solve the equation f(x) + 1 = 0.
Well, I tried this but got stuck. Here's what I did:
2-5cos^2(x) + 1 = 0
2+1 = 5cos^2(x)
3=5cos^2(x)
3/5=cos^2(x)
And then I'm drawn a blank. What to do next or if I've even done it right.
Any help is appreciated. :)
Alright, another functions related problem. This question came in 3 parts. I've done the first one but the other 2 are being a problem. Here it is:
Q. The function f is such that f(x) = 2 sin^2(x) − 3 cos^2(x) for 0 ≤ x ≤ p.
(i) Express f(x) in the form a + b cos^2(x), stating the values of a and b.
This was done easily. Answer came as 2-5cos^2(x) + 1 =0, where a=2, b=-5.
(ii) State the greatest and least values of f(x).
I think we have to make a graph of the function here. Problem is, there's cos^2 instead of just cos. I'm not sure how to do this. If there is some other way to find the problem, I'd like to try that too.
(iii) Solve the equation f(x) + 1 = 0.
Well, I tried this but got stuck. Here's what I did:
2-5cos^2(x) + 1 = 0
2+1 = 5cos^2(x)
3=5cos^2(x)
3/5=cos^2(x)
And then I'm drawn a blank. What to do next or if I've even done it right.
Any help is appreciated. :)