arcsin

[Arkan1k]

The function I need to perform is:

NPC Code:

---

arcsin(tan(30°))

---

But of course the graal engine doesn't supply both the arcsin and tan functions.
I found that:

NPC Code:

---

arcsin = arctan(x / (1 - x * x)^.5);

---

So what I have ended up with is:

NPC Code:

---

tan = sin(30)/cos(30); // tan(a) = sin(a)/cos(a)

val = arctan(tan / (1 - tan * tan)^.5);

---

But in (1 - tan * tan)^.5 I keep getting a negative value and because it's in a square root it's undefined.
The value I'm looking for is +/- 35.264° and I'm at a point where I am quite stuck at the moment.
Would anyone be able to help with this?