Problems with Tangent

[Boramina]

Hi! I have a problem, I want to calculate tan(90), but my program shows as result 1.63x10^16 and that's impossible, I don't know what's wrong, how can I fix it? Thank you in advance for the advice 🙂

P.S. I leave you a picture of my VI

[mikeporter]

You aren't calculating the tangent of 90 degrees, you are calculating the tangent of some number of radians. The tangent doesn't know about units, only values.

Mike...

[jcarmody]

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@Boramina wrote:

[...] my program shows as result 1.63x10^16 [...]

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Tan (90 degrees) = Opposite/Adjacent = 1/0

 https://www.google.com/search?q=Tan+(90+degrees)

[Bob_Schor · Accepted solution]

The tangent of 90° is infinite.  When LabVIEW attempts to compute it (probably through a series approximation), rounding errors creep in and you get a Very Large Integer, instead.  Look at the picture of the Tangent function -- see it approaching infinity at 90° (from the left) and rising from minus infinity as it crosses 90°?

Bob Schor

[altenbach]

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@Boramina wrote:

Hi! I have a problem, I want to calculate tan(90), but my program shows as result 1.63x10^16 and that's impossible,

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Well, you get the tan of a number that is very, very close to 90 degrees. Ideally you should get +inf. floating point operations involving fractional values are almost never exact.

If you take the arctan of +Inf, you get Pi/2, though.

Please explain what you mean by "impossible". We are dealing with numerical methods, not with symbolic math here.