calculate wrong or "/" work different

b=156260
c=165000
c\b


>> untitled3

b =

      156260


c =

      165000


ans =

    0.9470  !?!?!
    
    
    165000/156260=1.056 i use calc window

  
  
  

Answer 1

[Paul]

Hi pipor

The ldivide, .\ and mldivide, \, which is what you're actually using here, for the scalar case are mathematically (though not necessarily numerically) the same as

%c\b = (1/c)*b
b=156260;
c=165000;
c\b

ans = 0.9470

(1/c)*b

ans = 0.9470

What you did in the calc window used mrdivide, / which for scalar is the same as rdivide, ./, and does regular old division

c/b

ans = 1.0559

[pipor]

I don't understand why matlab has to make these complications..that if one accidentally misses the verse in a code and doesn't notice it, it's a mess...if I wanted to use the inverse as it is c\b I would do b/ C (invert the scalars)

[Paul]

I'm afraid I don't see the complication. In one case you were basically doing b/c and in the other c/b. For scalar b and c it is true that

b=156260;
c=165000;
b/c

ans = 0.9470

c\b

ans = 0.9470

isequal(b/c,c\b)

ans = logical
   1

are equal.

But in the question in the "calc window" you did the reciprocal

c/b

ans = 1.0559

b\c

ans = 1.0559

It all seems consistent and correct.

But do read the doc pages I linked above because there are difrences if b and/or c are non-scalar.

[Dyuman Joshi]

"I don't understand why matlab has to make these complications ..."

These are not complications. Those are different functions with different functionalities.

MATLAB is based on Matrices and both the functionalities have their own significance and use in linear algebra.

Nowhere in Mathematics is forward slash used for division of two numeric values. You, @pipor, yourself used the backward slash to get the result -

%Backward slash
%     v
165000/156260=1.056 i use calc window

But why forward slash here?

%v
c\b