Misaki

yes

Hold shift and press the cos^-1 button. on the calculator

Have you learned SOH CAH TOA yet? If so that's all you need to know really

maybe abstract trigonometry depending on if your school has that in it's syllabus

Number theory and algebra

Well find the indefnite integral first so

Let Train A=$A>\int \frac{\partial }{\partial x} A^e dx$

let train B=$\int_{\theta}^{\theta^\pi} A^\theta+\int A^\theta+1+\int A^\theta +2 +\theta$

Simplify And we get that $A=\int \pi^{B^\theta}+ B$Where B is a constant

Hope this helped!

Oh thanks. 

$\int_{0}^{\Large\frac\pi2} {\ln^{2}\left(\vphantom{\large A}\cos\left(x\right)\right) \ln^{2}\left(\vphantom{\large A}\sin\left(x\right)\right) \over \cos\left(x\right)\sin\left(x\right)}\,{\rm d}x$

I would say D is the safest bet.

multiply both sides by 3 so

x=30