1. ## Soh-cah-toa

This should be easy, but every time i type it in, i get the wrong answer! Please tell me what i am doing wrong!

Suppose is an angle in the second quadrant and

Then what is

and
.
And what is:

2. Originally Posted by MathNeedy18
This should be easy, but every time i type it in, i get the wrong answer! Please tell me what i am doing wrong!

Suppose is an angle in the second quadrant and

Then what is

and
.
And what is:

so first thing you do is draw your triangle (if you want to use that method, you can also use trig identities to do it--i'll show you if you're interested)

so now, our right-triangle has an acute angle called u, with the opposite side, length 2, the hypotenuse, length 3, and the other side, length sqrt(5) (by pythagoras' theorem).

so cos(u) = adj/hyp = sqrt(5)/3 ...but wait, we are in the second quadrant, cosine is negative. so cosu = - sqrt(5)/3

the tangent is also negative in the second quad. so
tanu = - opp/adj = - 2/sqrt(5)

and we have:

u = arcsin(2/3) = 41.8103149 degrees = 0.729727656 radians

This is my 14 th post!!!!

3. THANKS SOO MUCH! I forgot to put a negative sign!