matlab刘卫国附录实验3、4、5.docVIP

实验三 1. a=[-5 -3 1 2 2.5 3 5]; for i=1:6 x=a(1,i) if x0x~=3 y=x^2+x-6 elseif x=0x5x~=2x~=3 y=x^2-5*x+6 else y=x^2-x-1 end end 2.用if语句编写 grade=input(please input the grade which is between 0 and 100); a=floor(grade/10); if a=0a6 disp(E) elseif a=6a7 disp(D) elseif a=7a8 disp(C) elseif a=8a9 disp(B) elseif a=9a=10 disp(A) else disp(error!) end 用swich语句编写 grade=input(please input the grade which is between 0 and 100); if grade0 disp(error!) else switch fix(grade/10); case num2cell(0:5) disp(E) case{6} disp(D) case{7} disp(C) case{8} disp(B) case{9,10} disp(A) otherwise disp(error!) end end 3. t=input(请输入工作时长); if t120 y=84*120+(t-120)*84*1.15 elseif t60 y=t*84-700 else y=t*84 end 4. a=10+90*rand(1,2); a1=a(1) a2=a(2) b=fix(4*rand(1,1)); if b(1)==0 disp(运算法则为+) y=a1+a2 elseif b(1)==1 disp(运算法则为-) y=a1-a2 elseif b(1)==2 disp(运算法则为*) y=a1*a2 else disp(运算法则为/) y=a1/a2 end 5. a=100*rand(5,6) n=input(please input the no. of the line); if n==1| n==2| n==3| n==4| n==5 disp(a(n,:)) else disp(a(5,:)) disp(error!) end 实验四 用循环语句 y=0;i=0; n=[100 1000 10000] for j=1:3 for i=1:n(1,j); y=y+1/(i^2); z=sqrt(6*y); end disp(∏的值为:) z y=0; end 用向量运算 n=[100 1000 10000] for j=1:3 i=1:n(1,j); f=1./(i.^2); y=sum(f); z=sqrt(6*y); disp(∏的值为:) z y=0; end 2. n=1; y=0; while y3 y=y+1/n; n=n+2; end n y-1/n 3. a=input(please enter a) b=input(please enter b) x=1;n=0; while abs(x-a/(b+x))0.00001 if n=500 x=a/(b+x); n=n+1; end end x r=[(-b-sqrt(b^2+4*a))/2 (-b+sqrt(b^2+4*a))/2] s=r-x 4. clc f(1)=1; f(2)=0; f(3)=1; for n=4:100 f(n)=f(n-1)-2*f(n-2)+f(n-3); end disp([maximum is ,num2str(max(f))]) disp([minimum is ,num2str(min(f))]) disp([sum is ,num2str(sum(f))]) disp([正数个数为 ,num2str(length(find(f0)))]) disp([负数个数为 ,num2str(length(find(f0)))]) disp([零的个数为 ,num2str(length(find(f==0)))]) 5. j=0; s=0; for n=2:50 a=n*(n+1)-1; f