symbolic multiplication doubt in usage of * or .*

hi guys

I`m not sure of usage the .* or * and .^ or ^ in multiplying terms for example:

if:

syms Alpha

U21=(Alpha+(Alpha.^3/D21))*cos(Alpha*X1)/2;

then wich is correct:

u2=U21.*sin(Alpha2*Zeta2) or u2=U21*sin(Alpha2*Zeta2)

or in Alpha should I use .^ or only ^

thanks a lot

Answer 1

[KALYAN ACHARJYA]

* for scalar multiplecation

When you multiply a vector by a number, known scalar multiplication, example supoose

vec=[1,3,5,6];
m=2
result=m*vec

.* for vector dot multiplication, detail here

In the case

u2=U21*sin(Alpha2*Zeta2) 

[KALYAN ACHARJYA]

Same

>> a=[1 2 3 4]
a =

     1     2     3     4

>> a^2
Error using  ^ 
One argument must be a square matrix and the other must be a scalar. Use POWER (.^) for elementwise power.
 
>> a.^2

ans =

     1     4     9    16

>> b=3

b =

     3

>> b^2

ans =

     9

Answer 2

[atabak mostafavi]

Thank you Kaylan, and how about the ^ and .^ ?

Answer 3

[atabak mostafavi]

many thanks