matlab 高级

绘图

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条形图

x = [1:10];
y = [75, 58, 90, 87, 50, 85, 92, 75, 60, 95];
bar(x,y), xlabel('Student'),ylabel('Score'),
title('First Sem:')

等高线

[x,y] = meshgrid(-5:0.1:5,-3:0.1:3); %independent variables
g = x.^2 + y.^2;                     % our function
[C, h] = contour(x,y,g);             % call the contour function
set(h,'ShowText','on','TextStep',get(h,'LevelStep')*2)

3维图

[x,y] = meshgrid(-2:.2:2);
g = x .* exp(-x.^2 - y.^2);
surf(x, y, g); % surf(x, y, g)

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多项式

P(x) = x^4 + 7x^3 - 5x + 9P(x)=x4+7x3−5x+9

p = [1 7 0  -5 9];
polyval(p,4)
ans=693

X = [1 2 -3 4; 2 -5 6 3; 3 1 0 2; 5 -7 3 8]
polyvalm(p, X)
ans =

   2307  -1769   -939   4499
   2314  -2376   -249   4695
   2256  -1892   -549   4310
   4570  -4532  -1062   9269