Can you help me solve for arcsin(2) with complex numbers?

  • Thread starter Thread starter Craptola
  • Start date Start date
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 2K views
Craptola
Messages
14
Reaction score
0
Got a maths exam tomorrow been looking through some past papers. Have hit a stumbling block with regard to complex numbers, the problem lies with my algebra.

Homework Statement


Show that [itex]\arcsin(2) = \frac{\pi}{2}-i\ln (2\pm \sqrt3)[/itex]


Homework Equations


I'm fairly certain the way to solve this is to use
[tex]\sin(z)=\frac{1}{2i}(e^{iz}- e^{-iz})[/tex]


The Attempt at a Solution


Equating sin(z) to 2 I could only rearrange it to

[tex]4i=e^{iz}-e^{-iz}[/tex]
I was always pretty awful at algebra and can't see a way to rearrange for z. If anyone could nudge me in the right direction it would be greatly appreciated.
 
Physics news on Phys.org
The problem becomes simpler if you make the substitution [itex]v=e^{iz}[/itex].
 
When the question says "show that a=b", it gives you the option of working from the other end.