y|[gۑiUj𓚗z

 

1D

vO

yf_ex6_1.mz

function y=f_ex6_1(x)

% y=f_ex6_1(x)

y=x^2-exp(0.45*x)-5;

> x1=fminbnd('f_ex6_1',-10,10)

x1 =  0.25202

> y1=f_ex6_1(x1)

y1 =  -6.0566

 

 

2D

vO

yf_ex6_2.mz

function y=f_ex6_2(x)

% y=f_ex6_2(x)

y=5*sin(3*x)+1.5*x;

yex6_2.mz

t=-10:0.1:10;

y=f_ex6_2(t);

n=length(y);

k=0;

z=[];

for i=1:n-1

    if y(i)*y(i+1)<=0

        k=k+1;

        z(k)=fzero('f_ex6_2',[t(i),t(i+1)]);

@@@@if k>1 && z(k)==z(k-1)  % _i0.00000jd\̂h~

            k=k-1;

        end

    end

end

z

plot(t,y,z,f_ex6_2(z),'o')

grid('on')

legend('5sin(3x)+1.5x','Zero','location','northwest')

> ex6_2

z =

   -1.89307   -1.16635  0.00000  1.16635  1.89307