help! my life depends on it! (almost)

[Hulabaloo]

I have to prove that there really is spherical tangent function, Tan(a))=(sin(a)sinC))/(sin(b)cos(a)-sin(a)cos(b)cos(C)), by using the Tan (a)=sin(a)/Cos(a).
I've tried to solve it by inserting a sinus function and af cosinus function into the equation, but it doesn't really seems to work.
What am I supposed to do?

[Tormod]

Welcome, Hulabaloo.

I googled your function and the only page that came up is in Spanish:

http://www.bib.uab.es/pub/locus/11359722n5p117.pdf

Hope that is of any help...until Bo or any of our other maths wizards log on.

[pgrmdave]

Somewhat off topic, but why does your life (almost) depend on it?

[TINNY]

what is a spherical tangent function?

[Bo]

I have to prove that there really is spherical tangent function, Tan(a))=(sin(a)sinC))/(sin(b)cos(a)-sin(a)cos(b)cos(C)), by using the Tan (a)=sin(a)/Cos(a). I've tried to solve it by inserting a sinus function and af cosinus function into the equation, but it doesn't really seems to work. What am I supposed to do?

Hi! and welcome to these fora!

it doesn't work, since the formula you posted: Tan(a)=[sin(a)sin(C)]/[sin(b)cos(a)-sin(a)cos(b)cos(C)] doesn't hold for arbitrary a,b and c. To see this: you can rewrite the formula to:
sin(B)/sin(C)-cos(B)*(tan(A)/tan(C)=1.
Now take A=B=C=pi/4, and realize that tan(pi/4)=1. then you get: 1-cos(pi/4)=1. Since cos(pi/4) isn't zero (but sqrt(1/2)), this can't be true.

so you might have made a typo?
ps can anyone tell me why tormod makes strange posts about spanish cathedrals?

Bo

[Tim_Lou]

what function is this? a polar one?
or?

man.. i sux at 3d geometry

[maddog]

I think as Bo said that Hulabalo may have made typo somewhere, ...

Originally Posted by Hulabaloo

...I've tried to solve it by inserting a sinus function and af cosinus function into the equation, but it doesn't really seems to work.
What am I supposed to do?

Please tell me what a sinus function is (or a cosinus on for that matter) ?

What I understood of your equation/problem you are looking for a simplification of a tangent
function in spherical coordinates. Go to a library use one of the reference books on formulas
and constants at the reference desk. Or, goto a website like the one by Wolfram Research
(maker of Mathematica) or mathworks.com (maker or MATLAB). I think there is another one
called efunda.org (do a google search on efunda). Hope this helps.

Maddog