Question

f(θ) = (3cosθ−sinθ)^2

Answer 1

simplify the espression

Answer 2

\[(3\cos \theta-\sin \theta)^2=9\cos ^2\theta-6\sin \theta \cos \theta+\sin ^2\theta\]

Answer 3

Remember that sin^2(x) + cos^2(x)=1

Answer 4

1. f(θ) = 5−3sin2θ+4cos2θ
2. f(θ) = 4−3sin2θ+5cos2θ
3. f(θ) =−3+5sin2θ+4cos2θ
4. f(θ) = 4+4sin2θ−3cos2θ
5. f (θ) = 5+4sin2θ−3cos2θ
6. f(θ) = 3+4sin2θ+5cos2θ

Answer 5

its one of those answers

Answer 6

but idk which

Answer 7

6sinθcosθ = 3sin2θ - thats one bit of it done

Answer 8

1st one

Answer 9

ahh yes
8 cos^2 θ + cos^2θ + sin^2θ = 8cos^2θ + 1
and 8 cos^2 θ = 4cos2θ + 4
combine to give 1st one

Answer 10

\[9\cos^2\theta=9(1-\sin^2\theta)=9-9\sin^2\theta\]
Now add the sin^2 theta
\[9-9\sin^2\theta+\sin^2\theta=9+8\sin^2\theta\]

Answer 11

But
\[\sin^2\theta=\frac{1-\cos2\theta}{2}\]

Answer 12

Whoops. Sign error 9-8sin^2 theta

Answer 13

yup - very nice