What is sin-1(2i) equal?

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  • #1
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I could not found any answer to this question: What is sin-1(2i) equal?
 

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  • #2
matt grime
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sin(x) = (exp(ix)-exp(-ix))/2i

Firstly let y=exp(ix) and subs in

( y + 1/y)/2i=2i

solve for y, then for x.
 
  • #3
HallsofIvy
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Since you titled this thread "Multi-Valuedness", note that solving (y+ 1/y)/2i= 2i will involve solving a quadratic function so you may have two values for y. Then solving y= exp(ix) with both values of involves taking the logarithm which adds multiples of [itex]2\pi i[/itex].
 
  • #4
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For the two last posts, isn't it supposed to be (y - 1/y)/2i = 2i ?
 
  • #5
matt grime
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Yes - I can't even seem to follow my own suggestion.
 

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