two variables with known values in equations; use loop in matlab

1 view (last 30 days)
Hi I have question to ask. I have 3 variables with known variables, x, y, z.
x= 3, 1 , 4, 2, 1
y=3,4 ,5,1,1
z=2,2,1,2,2
I need to apply those variables in two related equations
d=x+y+2z
e=2d+xyz
how to solve this using loop
what I did
x=[3 1 4 2 1];
y=[3 4 5 1 1];
z=[2 2 1 2 2];
for i=1:length(x);
j=1:length(y);
k=1:length(z);
d=x(i)+y(j)+2*z(k)
d=d+1
e=2*d+(x(i)*y(j)*z(k))
end
did not work

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 29 Sep 2015
x=[3 1 4 2 1];
y=[3 4 5 1 1];
z=[2 2 1 2 2];
d=x+y+2*z;
e=2*d+x.*y.*z;
  4 Comments
Walter Roberson
Walter Roberson on 29 Sep 2015
The code that Andrei provided does all of them at the same time. No loop is required.
Norzuria Ibrahim
Norzuria Ibrahim on 29 Sep 2015
sorry.my mistake..you already told me how to wrote it above.anyway,thanks guys for your superb answers.

Sign in to comment.

More Answers (1)

WAT
WAT on 29 Sep 2015
Edited: WAT on 29 Sep 2015
It's a little unclear from your question, but if you mean you have 3 dependent variables (x,y,z) each observed at 5 different values of some independent variable (for example, x(t),y(t) and z(t)), and you want the values of c and e at those same times, then all you need to do is
d=x+y+2*z
e=2*d+x.*y.*z
The decimal in front of the multiply tells MATLAB to do the multiplication componentwise, rather than matrix multiplication.
Unless you're required to use a loop (for a HW assignment), in which case it would be something like
d = zeros(1,5);
e = zeros(1,5);
for i = 1:5
d(i) = x(i) + y(i) + 2*z(i);
e(i) = 2*d(i) + x(i)*y(i)*z(i);
end
But you don't want to do it this way unless you're explicitly required to use a loop.
  1 Comment
Norzuria Ibrahim
Norzuria Ibrahim on 29 Sep 2015
Edited: Norzuria Ibrahim on 29 Sep 2015
I think the code you wrote is right. But, the variables x, y and z have values like I wrote above. How to write the data of the variables in matlab and use loop?

Sign in to comment.

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Tags

No tags entered yet.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!