MATLAB: How to plot y = cos(pi/4)

plot

How do you plot y = cos(pi/4)? Thank you

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Choose upper and lower limits of x as a and b. Choose the desired number of plot points as n.

x = linspace(a,b,n);
y = repmat(cos(pi/4),1,n);
plot(x,y,’y-‘)

Related Solutions

MATLAB: How to plot a periodic signal f(t)= t.^3 , -pi<=t

x = linspace(-2*pi,2*pi,1000);
y = (mod(x+pi,2*pi)-pi).^3;
plot(x,y)

MATLAB: Nested loops to estimate cos(pi/4)

You should avoid calling your variable true, as that already has a meaning in MATLAB.
This line of code "for ea >= es" is not valid MATLAB syntax.
Your while loop is an infinite loop; you have not specified a way to break out of it.

Most of your line of code "est = 1+x^(k*2)/factorial(k*2)*(-1)^k" matches the term in the series definition of the cosine function, but the "1+" part doesn't.

Basically you want your code to look something like this pseudocode:

 1) initialize variables
 2) while (the approximation is not close enough to the known value)
 2a) add another term to your approximation

There's a while loop in step 2, but the condition is not 1. There is no for loop in the pseudocode. I can't say much more without simply giving you the code.

In general, if you're still unsure about how while loops work, I think one way you can understand them better is to walk through the first example (calculating factorial(10)) on its documentation page yourself, with you playing the role of MATLAB. Take a piece of paper and a pencil and "execute" each line yourself, recording the values of variables as they change on that paper. [When you reach the end statement, return to the while statement. If the while condition is not satisfied, go to the statement immediately after the end.]

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Related Solutions

MATLAB: How to plot a periodic signal f(t)= t.^3 , -pi<=t

MATLAB: Nested loops to estimate cos(pi/4)

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