matrix addition and substraction

{a1; a2; 0}

i want to R1-R1 and R2+R1

[Chaudhary P Patel]

i want to do both action at a time.

[DGM]

What are R1 and R2? Why can't you just add them as you wrote?

Why would it matter whether they happen simultaneously or sequentially?

What are the results assigned to? Are they being assigned to each other?

What does {a1; a2; 0} have to do with this?

[Chaudhary P Patel]

R1 and R2 are row 1 and row 2.

[Chaudhary P Patel]

Actually it is a 15X1 matrix of {a1;a2;0;a1;a2;0.....................;a1;a2;0}

so i want to do a1-a1 and a2+a1 for each set

Answer 1

[KSSV]

@pramod kumar What ou ask is a very basic question. I would suggest you to take a basic introductory course in MATLAB.

https://www.youtube.com/watch?v=qGiKv3-02vw

https://in.mathworks.com/support/learn-with-matlab-tutorials.html

https://in.mathworks.com/help/matlab/getting-started-with-matlab.html

Your question is simple.

% random matrix for demo
a1 = rand(15,1) ; 
a2 = rand(15,1) ; 
% add
a = a1+a2 ;
% subtract 
b = a1-a2 ; 

[Chaudhary P Patel]

Sir, my question is not to substract one matrix to another matrix.

I want to do R2= row2+row1

and R1= row1-row-1

[KSSV]

% random matrix for demo
a1 = rand(15,1) ; 
a2 = rand(15,1) ; 
id1 = 1:length(a1)-1 ; 
id2 = 2:length(a1) ; 
a = a1(id1)+a1(id2) ;
b = a1(id1)-a1(id2) ; 

[Chaudhary P Patel]

c=rand(15,1);
for i=1:3:length(c)
    a= c(i+1,1)+c(i,1);
    b=a(i,1)-a(i,1);
end

is it correct, Sir?

[KSSV]

This will throow error. It will not yun, as a is a scalar and you are trying to access it a svector.

[Chaudhary P Patel]

sir,

7.9710

7.9710

0

7.9710

7.9710

0

7.9710

7.9710

0

7.9710

7.9710

0

7.9710

7.9710

0

this is my column matrix and i have to 1,4,7,10,13 as zero by and 2, 5,8,11,14 row be Row2+row1, row5+row4, row8+row7, row11+row10, row14+row13.