How to plot a graph for variable cost per min of a product

I want to calculate total cost of a product on the bases of time as shown in the following script however I am unable to show on graph. I want to add second part of the curve with the 1st part. Thank you for helping me. and is there any command to fetch value from graph?

a = 10; %cost per min for 1st 3 mins b = 5; % cost per min for last 2 mins

x = 0:1:5; % time (5 mins) y = a*(x.*(x<=3)) + b*(x.*(x>3));

plot (x,y);

Total_Cost = a*3 + b*2 %40

Answer 1

[John Knollmeyer]

"I want to add the second part of the curve to the first part"

You could break your piecewise function into two separate functions and then concatenate them

first_component = a * (0:3);
second_component = b * (1:2) + first_component(4); 
y = [first_component, second_component];

"Is there any command to fetch value from the graph?"

If you save the function handle like so

figure_handle = plot(x,y);

then you can access the y values from it

Total_Cost_from_graph = figure_handle.YData(end)

Integral Tool

You didn't ask this in the question, but the integral tool is useful for problems like this

% y = 10, for 0 <= y <= 3
function_a = @(x) 10 * ones(size(x));

% y = 5,  for 4 <= y <= 5 
function_b = @(x) 5 * ones(size(x));

Total_Cost_Using_Integral = integral(function_1, 0, 3) + integral(function_2, 3, 5)