Why my graph only contain 4 lines instead of 6 lines

I defined a function which is calculate_pi, and using 6 different method to approxiamt the value of pi. The compute answer is correct, but when I use the answer to calculate the error between the value of pi in matlab, and plot the error in graph, it only shows 4 lines instead of 6 lines. I don't know why, can somebody help me? I appreciate that!

[VBBV]

Can you share the code for function calculate_pi instead of snapshot ?

Answer 1

[Nathan Hardenberg]

Check if your err-array for "left-hand" and "right-hand" has values in it. If thy are NaN, it does not plot a line, but no error is thrown

-- EDIT -- (after calculate_pi() Code)

Three of your methods result in the same graph ("left_end", "right_end" and "trapezoidal"). Thats why you are only able to see four graphs. I plotted with different linestyles to make it more obvious.

[Dan]

Thank you so much. I wonder if it's correct that they have the same value?