Hmmm. Arcsine, by definition, is the inverse of sine.
Since you have not learned yet of arcsine, your teacher/course material must mean for you to accomplish something else. There are other representations of arcsine than just saying “arcsine”.
Are you trying to plug into a calculator to get a numeric answer / graphical plot (as PnL seems to imply)? Or must you show your work to present a final answer equation?
Also, have you learned yet about derivatives, integrals, series, etc.? How about secant, cosecant, etc.?