Question

For a 2x2 matrix,

A = [a_ij], whose elements are given by a_ij = i/j

Write the value of a_12

I put the i = 1 and j = 2, then what? I'm forgetting things as I have an exam tomorrow :(

Answer 1

yes and have a look at the given rule : a_ij = i/j

Answer 2

first index represents the ROW number
second index represents the COLUMN number

Answer 3

a_ij is the element at i'th row and j'th column

Answer 4

In my mind I like to pair it with the idea of how in algebra we sometimes call slope "rise over run" just as a useful trick to help me remember what order they go in. Similarly here, you're "falling" for the first index and "running" for the second index.

Answer 5

So the answer is simply 1/2?

Answer 6

\[\large \left[ \begin{array}{ccc}

1/1 & \color{red}{1/2} & 1/3 \\
2/1 & 2/2 & 2/3 \\
3/1 & 3/2 & 3/3

\end{array} \right]\]

Answer 7

In fact, the matrix is completely meaningless to this question.

a_ij = i/j

means

a_12=1/2

Answer 8

thats the element at first row, and second column ^^

Answer 9

Oh Okay that's it? that's fairly simple :D

Answer 10

thats it ! we're just doing the new postman job :P

Answer 11

Wish I could give you both a medal @Kainui @ganeshie8 You guys are gonna help me pass my exam :')

Answer 12

locating the houses using the addresses