Question

Trig question

Answer 1

@TheSmartOne Can you help with this one?

Answer 2

I get no solution. But apparantly, that isn't right.

Answer 3

We need to use this identity.
cos(2x) = 1 – 2sin^2(x)

Answer 4

So:

\(\sf 6-sin(\theta) = 1 - 2sin^2\theta\)

\(\sf 2sin^2 \theta-sin \theta + 6 - 1 = 0\)

\(\sf 2sin^2 \theta -sin\theta + 5 = 0\)

Answer 5

Let's say \(\sf sin\theta = x\)

Then we need to factor

\(\sf 2x^2 - x + 5 = 0\)

Answer 6

Hm, I see. So, why do I not get the right answer when I graph both of them on my calc and they don't cross?

Answer 7

But even that method gives imaginary solutions.

Answer 8

To be honsest, I don't have a graphing calculator, so I had to learn how to do it manually. :P

Answer 9

Oh, ok, but don't you get imaginary solutions when you plug that into the quadratic?

Answer 10

I do, mhmmm. I guess they want the imaginary solutions to the question?

Answer 11

Hm, seems very strange.

Answer 12

Any thoughts, @Nnesha ?

Answer 13

i'll go with no solution
but ..hm i'm not sure sorry

Answer 14

@jim_thompson5910

Answer 15

Ok, thanks!