Terminal Arm Point P: Finding sin, cos, and tan for Θ in Standard Position

[Nelo]

Homework Statement

The coordinates of a point P on a terminal arm of an <Θ (theta) in standard position are given, where 0<Θ<2pi. Determine the exact values of sinΘ, cos Θ and tan Θ

2h) (-2,6)

Homework Equations

r= X +y

The Attempt at a Solution

So, first i found r by using r^2 = x^2 + y^2

and got r = √ 38

Since √ 38 cannot be factored to any lower form, i left that as the r.

Going to sin, I did op/hypotenuse

and got 6/√ 38 . However, this seems to be completely wrong as the answer is somehow 3/√ 10

I just don't see how that possible, anyone?

 

[LCKurtz]

You forgot to square the x coordinate when you calculated r.

 

[Nelo]

oops, thanks sir.