Point P(3, 9) is on the terminal arm of an angle q in standard position. Determine the exact value of θ.

Answer 1

Because our point (3,9) is on the terminal arm of our angle q, this means that the arm is the hypotenuse of a right triangle where the leg adjacent to θ is 3 and the leg opposite to θ is 9. Since tangent of θ is opposite/adjacent, we know that tan θ = 9/3. On a calculator, one would type in tan^-1(9/3) = θ.

Answer 2

Have you tried Tan-1(9/3)?