例7-29  用int函數(shù)求符號(hào)積分。
解：在命令窗口中輸入如下命令，并按Enter鍵確認(rèn)。
>> syms x x1 alpha u t;
>> A = [cos(x*t),sin(x*t);-sin(x*t),cos(x*t)]
A =
[  cos(x*t),  sin(x*t)]
[ -sin(x*t),  cos(x*t)] 
>> int(1/(1+x^2))
ans =
atan(x)
>> int(sin(alpha*u),alpha)
ans =
-1/u*cos(alpha*u)
>> int(besselj(1,x),x)
ans =
-besselj(0,x)
>> int(x1*log(1+x1),0,1)
ans =
1/4
>> int(4*x*t,x,2,sin(t)) 
ans =
2*t*(sin(t)^2-4)
>> int([exp(t),exp(alpha*t)]) 
ans =
[               exp(t), 1/alpha*exp(alpha*t)]
>>  int(A,t)
ans =
[ 1/x*sin(x*t),  -cos(x*t)/x]
[   cos(x*t)/x, 1/x*sin(x*t)] 
>>