sin and cos

[alkatran]

I need to know the opposite of sin and cos (sin-1 on calculators)

From what i understand there's no vb function for these, can
anyone give me one? so if i put:

print asin(sin(5))     'this will print 5
print acos(cos(5))    'this will also print 5

help?

[SteveCRM]

last I checked there was

[gwdash]

there aren't

They are dirived as follows (from vb-help):

Inverse Sine: Arcsin(X) = Atn(X / Sqr(-X * X + 1))
Inverse Cosine: Arccos(X) = Atn(-X / Sqr(-X * X + 1)) + 2 * Atn(1)

[alkatran]

Private Function Arcsin(X As Double)
Arcsin = Atn(X / Sqr(- X * X + 1))
End Function
 
Private Function Arccos(X As Double)
Arccos = Atn(-X / Sqr(-X * X + 1)) + 2 * Atn(1)
End Function

this causes an error (incorrect prcedure call) for some reason.
any ideas?

[gwdash]

try deleteing the space after the first "-" sign

[alkatran]

Print Sin(Arcsin(5))
 
Public Function Arcsin(X As Double)
Arcsin = Atn(X / Sqr(-X * X + 1))
End Function

creates an error, maybe im just using it wrong too, u give arcsin an angle and a measurement? or 2 measurements?

[gwdash]

You give arcsin a value between 0 and 1 inclusive, the output of a sin command. It will return the number of radians (pi radians=180 degrees). The number you give it is the ratio formed

from SOH-CAH-TOA

so for arcsin, you feed it the Opposite/Hypotenuse and it gives you the angle. You can't give it a number greater than one b/c by definition, in a right triangle, the hypotenuse is the longest side.

[alkatran]

radians, got it, thx

my new line..

Deg(Sin(Arcsin(Rad(40))))

... works though