Question

If cosx= 0.8, and 0 12 years ago

Answer 1

I know that x is in the first quadrant, but need more guidance.

Answer 2

You know the value of cos(x). Now find sin(x). Because 2sin(x)cos(x) = sin(2x), you now know what the value of sin(2x) would be. From that, figure out cos(2x). Then use tan(2x) = sin(2x)/cos(2x)

I hope I made sense.

Answer 3

Note that sin(x) = sqrt(1 - cos^2(x)) so you can find the value of the other one.

Answer 4

kk, I said guidance not work, thank you for the help.

Answer 5

I know from here I think.

Answer 6

OR 0.8 = 4/5 = cos(x). This seems like a 3-4-5 triangle.

Answer 7

No problem haha! I totally wrecked the previous question.

Answer 8

No, I am actually pretty stupid.
i keep trying to do this but come back to co(x)=0.8 every time, dky.