Question

tan theta = 20/21.
Find sin(2theta) if theta is between pi and 2pi/3

PLEASE HELP. THANK YOU!

Answer 1

Do you know what Sin(2theta) is equal to. Recall your trig identites.

Answer 2

2sin theta cos theta

Answer 3

Good :) .

Answer 4

Now draw a triangle.

Answer 5

Ok

Answer 6

But be careful. It says Theta is between pi and 2pi/3 . Do you know what quadrant that refers to?

Answer 7

Third right?

Answer 8

Good job!

Answer 9

wait 2nd?

Answer 10

No it's 3rd :) .

Answer 11

oh ok

Answer 12

i thought it was 4pi/3 in third...

Answer 13

No it's 2pi/3 :) .

Answer 14

Ohh wait!!!

Answer 15

ok

Answer 16

shouldn't the 270 degrees be 3pi/2?

Answer 17

yeah. My mistake XD .

Answer 18

I was about to fix that.

Answer 19

lol everyone makes mistakes

Answer 20

I probably lured you to make the mistake when i first said it was in the 3rd quad