1.坐标轴修饰
axis equal；axis([0,6,0,6])
不修饰则为默认网格
grid on
2.不太漂亮的pretty命令
3. Laplace变换
syms t s a b
f1=exp(-a*t)*sin(b*t)
F1=laplace(f1,t,s)
4. 逻辑计算
>> A=[-2,-1,0,0,1,2,3]
A =
-2 -1 0 0 1 2 3
>> L1=~(A>1)
L1 =
1 1 1 1 1 0 0
>> L2=(A>0)&(A<2)
L2 =
0 0 0 0 1 0 0
5. Legend修饰
>> t=(0:0.02:2)*pi;
x=sin(t);y=cos(t);z=cos(2*t);
plot3(x,y,z,’b-‘,x,y,z,’bd’)
view([-82,58]),box on
xlabel(‘x’),ylabel(‘y’),zlabel(‘z’)
legend(‘ 链’,’ 宝石’,’Location’,’best’)
6. 函数取值
Replace variables x and y with these 2-by-2 matrices. subs expand the scalars x and y to arrays of the same size and performs substitutions:
syms x y
subs(x*y, {x, y}, {[0 1; -1 0], [1 -1; -2 1]})
ans =
0 -1
2 0
Note that these substitutions are elementwise:
[0 1; -1 0].*[1 -1; -2 1]
ans =
0 -1
2 0
subs(x+y, {x, y}, {[0 1; -1 0], [1 -1; -2 1]})
ans =
1 0
-3 1
注意：
Assign the expression x + y to f:
syms x y
f = x + y;
Replace y in this expression with the value 1. Here f itself does not change:
subs(f, y, 1); f
f =
x + y
To replace the value of f with the new expression, assign the result returned be subs to f:
f = subs(f, y, 1);
f
f =
x + 1
