Question

quick trig check

find values of sin2a, cos2a, and tan2a when sina=-2/3 and this is in the 3rd quadrant

Answer 1

2 ways there, use double angle formulas or solve for a then plug and chug

Answer 2

I'm getting
\[\sin 2a=\frac{ 4\sqrt{5} }{ 9 }\]
cos2a=\[\frac{ 1 }{ 9 }\]
tan2a=\[4\sqrt{5}\]

Answer 3

so yea third side is (\sqrt 5\) I agree with sine

Answer 4

h/o for the other two

Answer 5

I agree with cosine

Answer 6

and tangent?

Answer 7

and I agree for tangent as well

Answer 8

looks good to me, make sure you define the third side and show how you got it in your work

Answer 9

yup, did that. thanks for checking.

Answer 10

np, good job