|Re: graphing/solving with 50g|
Message #3 Posted by Crawl on 20 Oct 2011, 6:08 p.m.,
in response to message #1 by Robin Shelton
For 2, that's a homogeneous equation which means it has a trivial solution of x=y=z=0.
In general, for systems like that, I would enter them as matrices.
[7 6 9]
[5 6 20]
[1 1 1]
(It's easiest to enter with the Matrix writer)
Then hit 1/x.
If the system of equations is not linear, you can use the command MSLV. This is an advantage the 50g has over the TI89, by the way; the TI89 has no built-in function for solving systems of nonlinear equations.
For the last one, it looks to me like the integrand is the constant value 12, so yes, 12 * 2 pi / 3 = 8 pi.
I get the question mark when I evaluate that integral, too. Two ways around it: In approximate mode, you'll get the correct numerical value. To get it exact, when the integral is in level 1 of the stack, instead of hitting EVAL, hit TSIMP. (To simplify trigonometric expressions) It immediately gives 8pi.