Output of array formulas

[dryper]

The following 2 array formulas are similar but different:

FIRST

SECOND

Can someone explain how array formulas are evaluated? I was actually expecting the output for SECOND image to be just 70.

Thanks.

 

[GlennUK]

You have a row of values being multiplied by a column of values, and vice versa... I would expect the result to be transposed as you show. Can you explain why you think 70 would be an answer?

 

[dryper]

Sorry, I meant my expected answer is 70 for FIRST array formula, not SECOND.

Here's a simple example:
1) Go here: http://www.bluebit.gr/matrix-calculator/matrix_multiplication.aspx

2) Enter this for FIRST array formula and press "Multiply A*B":

3) Enter this for SECOND array formula and press "Multiply A*B":

4) Some notes on Matrix Multiplication: http://www.mathwarehouse.com/algebra/matrix/multiply-matrix.php

 

[GlennUK]

Have a look at the MMULT worksheet function.

 

[dryper]

Have a look at the MMULT worksheet function.

MMULT works as I expected, thanks. So I guess the question that remains; how is the FIRST array formula {(1,2,3,4)*(5;6;7;8)} evaluated?

 

[GlennUK]

MMULT works as I expected, thanks. So I guess the question that remains; how is the FIRST array formula {(1,2,3,4)*(5;6;7;8)} evaluated?

Like this:

Excel Workbook
	A	B	C	D	E	F	G	H	I
1	5	10	15	20		1*5	2*5	3*5	4*5
2	6	12	18	24		1*6	2*6	3*6	4*6
3	7	14	21	28		1*7	2*7	3*7	4*7
4	8	16	24	32		1*8	2*8	3*8	4*8
Sheet1