problem in writing matlab code (To Plot)

I want plot the function A versus x, can't write the program for the following algorithm.

A= K for x <= 0; K is a constant

A= K/2 (1+cos x) for 0<x<50;

A= 0 for x >= 50

i have used the if elseif else end statement, but not not succeed.

[Thorsten]

Please show us your code.

Answer 1

[Thorsten]

 K = 1;
 x = linspace(-100,100);

 A = K/2*(1 + cos(x));
 A(x<=0) = 1;
 A(x>=50) = 0;

 plot(x,A)