function to increase the range of inverse sine

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rick il 14 Set 2011
Modificato: Walter Roberson il 26 Ott 2018
The asin() function only returns values between (-pi/2, pi/2). How can I write a function to give me values between (0, 2pi)?

Risposte (3)

Walter Roberson
Walter Roberson il 14 Set 2011
  1 Commento
Jan il 14 Set 2011
This will solve the problem by using the MATLAB 2013a or later. Not very efficient...

Accedi per commentare.

the cyclist
the cyclist il 14 Set 2011
You can force the output to be within the range (0,2pi) by applying the mod() function:
>> mod(asin(x),2*pi)
Given only one input argument, you can't infer precisely which quadrant to return. Walter's answer points to a list of requested features (specifically, more two-argument versions of inverse trig functions).

theodore panagos
theodore panagos il 26 Ott 2018
Modificato: Walter Roberson il 26 Ott 2018
You can have the asin(x,y) from 0 to 2*pi by the formula:
asin(x,y)=pi-pi/2*(1+sgn(x))*(1-sgn(y^2))-pi/4*(2+sgn(x))*sgn(y) -sgn(x*y)*asin((abs(x)-abs(y))/sqrt(2*x^2+2*y^2))
there is x=x2-x1 and y=y2-y1

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