How do I use trap?

Question

Mark Dillon 2015-8-4

0
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https://ww2.mathworks.cn/matlabcentral/answers/232250-how-do-i-use-trap

回答： Al Dente 2015-8-4

Here is what I am working with right now:

if true
  %     %%Write a script to integrate a function in three different ways: 
   % by eyeballing it, by calling trapz with a list of points, 
   % and by calling integral with a function.
    % Equation we’re going to integrate: y(x) = -2x^4+3x+5. 
    % We’re going to integrate from -1 to 1.
    y = @(x) -2.*x.^4+3.*x+5;
    x = -1:1;
    % Plot x vs y
    fplot(y, [x(1),x(end)]);
    grid on
end

Now I need to use trapz to figure out how to calculate the area under the curve, but I cannot figure it out. I tried Area = trapz(x,y), but that didn't work? How to a solve this problem?