butterysteez Posted May 9, 2003 Share Posted May 9, 2003 I'm just messing around with some computer graphics and I got a little over my head in the math. I need to find the normal to this plane which I'm using to model water splashes. 0=(sin sqrt(x^2 + z^2))/(x^2 + z^2)-y Link to comment Share on other sites More sharing options...
Tom Mattson Posted May 15, 2003 Share Posted May 15, 2003 Do the partial derivatives one at a time. You wrote this as a quotient, but I like to rearrange complicated functions so that I never have to use the quotient rule, like so: f(x,y,z)=(sin((x2+z2)1/2))(x2+z2-y)-1 fx=(cos((x2+z2)1/2))(1/2)(x2+z2)-1/2(2x)(x2+z2-y)-1+(sin((x2+z2)1/2))(-1)(x2+z2-y)-2(2x) fx=xcos(((x2+z2)1/2))*(x2+z2)-1/2*(x2+z2-y)-1-2xsin(((x2+z2)1/2))*(x2+z2-y)-2 Happily, x and z occur symmetrically in this function, so you can find fz by simply swapping x<-->z in the above derivative. Finally, fy=sin((x2+z2)1/2)(x2+z2-y)-2 Tom Link to comment Share on other sites More sharing options...
butterysteez Posted May 16, 2003 Author Share Posted May 16, 2003 thanks a bunch man. do you want me to email you the program or the source? Link to comment Share on other sites More sharing options...
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