- #1
Saladsamurai
- 3,020
- 7
I was watching the MIT opencourseware lecture #1 by Gilbert Strang last night. He attempts to introduce two different ideas in this lecture.
The first is that a system of equations, let's use 2 eqs & 2 unknowns for example, can be viewed from a row picture. This is the way I am used to looking at it. Each row represents the EQ of a line and where those two lines intersect is the solution to the system.
The second is that the system can be viewed from the column picture. That is if we have the following system:
[tex]\begin{array}{c}a_1x+b_1y=c_1 \\ a_2x+b_2y=c_2\end{array}[/tex]
we can look at each column as a vector like this:
[tex]x\left[\begin{array}{c}a_1\\a_2\end{array}\right]+y\left[\begin{array}{c}b_1\\b_2\end{array}\right]=\left[\begin{array}{c}c_1\\c_2\end{array}\right][/tex]
And in doing so, we now seek to ask what the proper multiples of the column vectors are such that when added, they yield the correct answer.
He then drew it out, that is he showed how it worked geometrically.
I am a little confused. I can see that it does indeed work. But I do not see why? Why should the columns be treated as vectors? How are they related? They seem to me to be completely separate entities... How did one discover that this method will work?It is hard to put my question into words, so if I am being to vague or unclear, please yell at me.
The first is that a system of equations, let's use 2 eqs & 2 unknowns for example, can be viewed from a row picture. This is the way I am used to looking at it. Each row represents the EQ of a line and where those two lines intersect is the solution to the system.
The second is that the system can be viewed from the column picture. That is if we have the following system:
[tex]\begin{array}{c}a_1x+b_1y=c_1 \\ a_2x+b_2y=c_2\end{array}[/tex]
we can look at each column as a vector like this:
[tex]x\left[\begin{array}{c}a_1\\a_2\end{array}\right]+y\left[\begin{array}{c}b_1\\b_2\end{array}\right]=\left[\begin{array}{c}c_1\\c_2\end{array}\right][/tex]
And in doing so, we now seek to ask what the proper multiples of the column vectors are such that when added, they yield the correct answer.
He then drew it out, that is he showed how it worked geometrically.
I am a little confused. I can see that it does indeed work. But I do not see why? Why should the columns be treated as vectors? How are they related? They seem to me to be completely separate entities... How did one discover that this method will work?It is hard to put my question into words, so if I am being to vague or unclear, please yell at me.