How to transform function in MatLab? Shift, Scale etc.

If I have a function as follows:

syms x1;
syms t;
x1 = exp(t)* Heaviside(2*t);

How do I do define x2 = x1(t-2) so I can plot it. I would rather not have to redefine the entire function doing the work myself each time I want to do a transformation. Is there a way of achieving this?

[Preetha Thanunathan]

I have a function f(x) whose range is the interval [0, 1], and I need to shift it and stretch it so that the range is now the interval [a, b]. Find a function g(x) (defined in terms of f(x)) so that g(x) has an range [a, b].

In Matlab, the rand command produces a random number between 0 and 1, under the uniform distribution; that's different from the normal distribution. The graph of the uniform probability distribution is a horizontal line. The graph of the normal distribution is the bell curve.

I need a program that will accept input values a and b, a < b, and will output a random number between a and b, You'll do this by shifting and stretching the rand function. Notice that in Matlab the rand function doesn't take an input. You just type rand and hit enter, and the program will spit out a random number between 0 and 1.

can anyone answer this question

Answer 1

[ha9981]

http://www.mathworks.com/help/symbolic/subs.html

I think I found it. Appears to work.

x3 = subs(x1, t, t-2)

Is this a correct and reliable way?

[Wayne King]

ahh yes, I forgot about subs!

[Azzi Abdelmalek]

If you want to delay with t0, compute x(t) then plot(t+t0,x)

Answer 2

[Wayne King]

I don't know of a shift operator for symbolic functions.

   syms t
   tprime = t-2;
   x1 = exp(t)*heaviside(2*t);
   x2 = exp(tprime)*heaviside(2*tprime);

Or just:

   x2 = exp(t-2)*heaviside(2*(t-2));

[ha9981]

That will not work. Please recheck your code if you have time. Also without a shift function I might as well shift the function myself and redefine it. I am not sure why I cannot do something like this: x2(t) = x1(t-2)

Is there a way to do it without symbolic functions?

[Wayne King]

I'm not sure what you mean by recheck your code.

[ha9981]

You fixed it now. It said xprime before so it wasn't going to work.

Answer 3

[Azzi Abdelmalek]

syms t x
x1 = exp(t)* heaviside(2*t);
t=0:.1:10
if you want to plot |x1(t-2)| then
y=eval(x1)
t=t+2  % not t=t-2  because it's a delay 
close;plot(t,y)
set(gca,'xlim',[0 max(t)])