Multivariable Calc





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By Smeds (Smeds) on Thursday, September 30, 2004 - 06:02 pm: Edit

Since so many people here on CC are so ubber-smart, I'm hoping someone can help me with a math question I have. Here's the problem. I have to write an equation of the plane that is determined by two lines.

Line 1: (x-6)/-6 = (y+1)/2 = z/-3
Line 2: (x-4)/2 = (y-3)/1 = (z+1)/1

I just need to find a point from one of the lines (x1, y1, z1) and then vector , to plug into a(x-x1)+b(y-y1)+c(z-z1)=d, right? My question is how to find that point. Thanks a million to anyone who can help!

By Averagemathgeek (Averagemathgeek) on Thursday, September 30, 2004 - 06:52 pm: Edit

First, you find the cross product of two vectors representing each line. Use this to find something of the form ax+by+cz=d. Now you need d. Just pick some number (think about what number will be easiest) for any of the coordinates. Use one of the lines to find the other coordinates. Plug them into ax+by+cz=d, and then d will be right there.

Hope this helps.

By Smeds (Smeds) on Saturday, October 02, 2004 - 12:50 pm: Edit

Ahh, thank you so much!


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