HP50g or other: U. of Houston calc exams

08092015, 10:28 PM
(This post was last modified: 08092015 10:51 PM by Hlib.)
Post: #19




RE: HP50g or other: U. of Houston calc exams
Thanks, CR Haeger and Gilles, you rescued me from a failure at exam :)
On a statement of the problem we have to find parameter "a" without solving system of the linear equations. You simply solved ordinary system, having replaced "a" with "z": 2x 3y = 6  7z 3x + 5y = 7+ 2z 7x +11y = 4  6z I have the same result. It seems to me, it is not a proved trick. We must have: rank[[2 3][3 5][7 11]]=rank[[2 3 67a][3 5 7+2a][7 11 46a]]<=2, therefore det[[2 3 67a][3 5 7+2a][7 11 46a]]=0. Code: [[2 3 ′6  7a′ ] [3 5 ′7+ 2a′] [7 11 ′4  6a′]] DET 0 = ′a′ ZEROS Initially I was going to solve quite so. What would you do, if: 2x 3y = 6  7*SQ(a) 3x + 5y = 7+ 2a 7x +11y = 4  6a ? 

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