Thread:GreatDestroyer12/@comment-1073312-20130212002727

Hello, I'll show you my maths problem.

I don't have an issue with understanding the equation and how it works (physical side of things), but I've tried for hours to work out to re-arrange the infernal thing, and I can't match the answer I get with what a helper showed me.

Okay so we have a seismic wave coming along a horizontal rock interface at an incident of 30 degrees. There is a) the angle of refraction and b) the critical angle. Snell's Law states that the angle theta is a constant so when velocity (v) changes, so does theta. $$\frac{\sin\theta_1} = \frac{\sin\theta_2} = \frac{1}{v_2}$$

With units: sin30/1500 = sinƟ2/2300

I know that the answer of 50.5 degrees (assuming my helper was right), but since I'm failtastic at applying maths, if you could show me how to get there step by step it would be great.

Then for critical angle:

⇒Ɵc = sin-1$$\frac{v_1}{v_2}$$

That equation looks straightforward but I'm finding it hard to select sin-1 on my calculator.

 