Eqn of Plane passing through a point and perpendicular to another plane's traceby Stumbleinn Tags: passing, perpendicular, plane, point, trace 

#1
Aug2508, 06:46 PM

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1. The problem statement, all variables and given/known data
Here's the problem:Find the equation of the plane passing through the point (3,1,4) and perpendicular to the trace of the plane x3y+7z3=0 in the xy plane. 2. Relevant equations to me this should be as easy as finding the two coordiates of the plane's traces on the x and y axis. ie (3,0,0) and (0,1, 0). Since these two points and the point (3,1,4) determine the plane. 3. The attempt at a solution since the general form of the plane is Ax+By+Cz+D=0. I should get 3 equations that look like this: 1) 3A+D=0 2) B+D=0 3) 3A+B+4C+D=0 1) implies that D/A=3 and thus D=3 and A=1 substituting into eqn2 yields B=3 and sunstituing into eqn3 gives C=9/4 so the eqn should be x3y+9/4Z3=0 or 4x12y+9z3=0 However the answer in the book is 3x+y+8=0. I find that the book is rarely wrong and usually it's me that is confused. Please advise on where I went wrong Thanks so much 



#2
Aug2508, 07:37 PM

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