|Sep15-12, 06:29 AM||#1|
matrices and quadratic basics help
I have figured out the answer to the question, but I have no idea why and how it works.
I have attached a copy of the question. I do apologize I am still having trouble putting in to latex, I can install some but not all, so bare with me.
So if I multiple out the matrices I get [itex]\chi[/itex]2 + 10[itex]\rightarrow[/itex] I then minus this from the quadratic [itex]\chi[/itex]2 + 8[itex]\chi[/itex] + 10 = 0 [itex]\rightarrow[/itex] Which then gives me 8[itex]\chi[/itex] = 0
reagrange and I have [itex]\chi[/itex] = -8
Which is the right answer, I checked the mark scheme but I am suppose to find the value of K and not x. This make me think I have done the wrong maths but got the right answer.
Could someone point out if I have gone wrong, it would be very helpful.
It is the one highlighted.
|Sep15-12, 09:04 AM||#2|
Hey Taylor_1989 and welcome to the forums.
Expanding your equation gives x^2 + 10 = kx which implies x^2 - kx + 10 = 0. But we know the equation is x^2 + 8x + 10 = 0 which means -k = 8 so k = -8.
Remember you know the equation, and you are finding the value of k when you expand your matrix multiplication and collect terms: solving for x is finding the roots of the function where you are solving x^2 + 8x + 10 = 0 for the variable x.
|Sep15-12, 12:23 PM||#3|
|Similar Threads for: matrices and quadratic basics help|
|Electricity Basics and Battery basics||General Physics||3|
|Quadratic Form and matrices question||Calculus & Beyond Homework||0|
|quadratic forms of symmetric matrices||Linear & Abstract Algebra||6|
|Basics of quintic and quadratic expressions||Introductory Physics Homework||1|
|Basics of multiplication of matrices||Linear & Abstract Algebra||8|