Math Question

[lightnb]

IF

A = 2(TAN(F*F))

How do you re-write the formula to solve for F?

[peterska2]

so

A = 2(TAN(F Squared)

A = Tan(F squared) + Tan (F squared)

A/Tan = (f squared) + (f squared)

A/Tan = 2(f squared)

A/(2 Tan) = F squared

square root (A/(2 tan)) = F

Could be wrong, coz it's a long while since I last did algebra though.

[Freesteyelz]

*Sigh* I feel so inadequate. :lick:

[Adrian Schneider]

F = squareroot(inversetan(a/2);

My work:

a = 2tan(F*F);
a/2 = tan(F*F);
iTan(a/2) = F*F
2root(iTan(a/2)) = F;

[Xenium]

Me too.. F = SQUAREROOT(INVERSETAN(A/2))

@peterska2. The inverse of TAN is INVERSETAN not divide tan

A = 2(TAN(F*F))
A = 2(TAN(F^2))
A/2 = TAN(F^2)
INVERSETAN(A/2) = F^2
F = SQUAREROOT(INVERSETAN(a/2))

[peterska2]

I knew it was probably wrong, but it's a long while since I last did algebra.

[lightnb]

Thanks guys

I was never too good at algebra...

is inverse tangent the same as arc tangent?

in other words, would:

PHP Code:

$F = SQRT(atan($A/2)); 


be the correct PHP syntax for this?

[Xenium]

Yes. Arc tan is the inverse of tan for php.

But the return is in radians. So if you want it in degrees, you will need to use rad2deg.


E.G.

PHP Code:

$F = SQRT(rad2deg(atan($A/2))); 


[lightnb]

$A should be in degrees. $f should be a decimal

[who is chris c]

just a fyi you cant divide normal trig fnct (sin, cos, tan) by both sides like normal you need to take the inverse (^-1) to do the equalitive property been awhile but thought i'd throw that in