MATLAB 输入百分制成绩的行向量，调用编写的函数文件求得五级制成绩。

问题1

function Rank = TranGrades(fen)

len = length(fen);
Rank = [];
for k = 1:len
CurMark = fen(k);
if CurMark>=90
Rank = strcat(Rank,'A');
continue;
end
if CurMark>=80
Rank = strcat(Rank,'B');
continue;
end
if CurMark>=70
Rank = strcat(Rank,'C');
continue;
end
if CurMark>=60
Rank = strcat(Rank,'D');
continue;
end
if CurMark<60
Rank = strcat(Rank,'E');
continue;
end
end
测试结果：
fen=[90,85,100,79,57];
Rank = TranGrades(fen)
Rank =

ABACE

问题2
syms x
f = x+cos(x)
an1 = subs(f,x,0)
an2 = subs(f,x,pi/2)

结果：
f =

x+cos(x)

an1 =

1

an2 =

1.5708