Question

用matlab画一个函数图象如y=x.^2-4*x+5,怎么找出图象上最大值点得坐标

Answer 1

syms x

ff=x^2-4*x+5;

ff1=diff(ff);

xx=0:.2:4;yy=subs(ff,x,xx);

a1=double(solve(ff1));ya1=double(subs(ff,x,a1));

plot(xx,yy);

hold on

plot(a1,ya1,'b*');

text(a1,ya1,'极小值点');

只有极小值点,开口向上