Question

if tanx=5/3, pi 12 years ago

Answer 1

tangent = opposite / adjacent

the second piece of information is telling us that our angle x is in the 3rd quadrant.

Answer 2

sin2x?
Umm I guess we can use our Double Angle Identity.\[\Large\rm \sin2x=2 \sin x \cos x\]

Answer 3

Use the Pythagorean Theorem to find the missing side of the triangle.
Then substitute in the relationships for sine and cosine.

Understand how to proceed?

Answer 4

Oh since we're in the 3rd quadrant, I guess I should have labeled both the x and y direction as negative.