for loop question help

Use a ‘for loop’ to compute and plot the following function over the interval -2pi<= x <= 2pi:

for x < -pi g(x)=cos(x)+2

for x => -pi and x<=pi g(x)=2

for x>pi g(x)=cos(x)-2

Plot g versus x for x from -2pi to +2pi (x on the horizontal axis, g on the vertical). All the three functions should be plotted in one diagram (one waveform).

Use at least 100 points in your x vector so you get a smooth curve. Label your graph.

I need help with this one also.

thanks

[Stephen23]

@Terrell Curley: I notice you are just getting madhan ravi to do all of your homework for you. Hopefully you are aware that:

1. you will learn more by trying yourself first.
2. using madhan ravi's code without attribution is plagiarism.
3. your professor/tutor can find this website just as easily as you can.

Answer 1

[madhan ravi]

Read about logical indexing and labels

without loop (efficient)

x=linspace(-2*pi,2*pi);
g(x<pi)=cos(x(x<-pi))+2;
idx = ( x >= -pi ) & ( x<=pi )   ; 
    g(idx)=2;
 g(x>pi)=cos(x(x>pi))-2;
plot(x,g,'r')

with loop (inefficient)

x=linspace(-2*pi,2*pi);
g=zeros(1,numel(x));  %pre-allocation for speed and efficiency
for i =1:numel(x)
if x(i)<-pi;
    
    g(i)=cos(x(i))+2;
elseif x(i) >= -pi && x(i)<=pi   ; 
    g(i)=2;
else x(i)>pi     ;
    g(i)=cos(x(i))-2;
    
end
end
 
plot(x,g,'r')