控制系统仿真(MATLAB)实验2

MATLAB实验二

自动化2班解洪超200940600138

一、实验目的：

1. Learn to design branch and loop statements program

2. Be familiar with relational and logical operators

3. Practice 2D plotting

二、实验内容：

1. Assume that a,b,c, and d are defined, and evaluate the following expression.

a=20; b=-2; c=0; d=1;

(1) a>b; ans= 1(2) b>d; ans= 0

(3) a>b&c>d; ans=0

(4) a==b; ans= 0 (5) a&b>c; ans=0

6) ~~b; ans=1

a=2; b=[1 –2;-0 10]; c=[0 1;2 0]; d=[-2 1 2;0 1 0];

(7) ~(a>b)

ans =

0 0

0 1

(8) a>c&b>c

ans =

1 0

0 1

(9) c<=d

Error using ==> le

Matrix dimensions must agree.

a=2; b=3; c=10; d=0;

(10) a*b^2>a*c ans= 0 (11) d|b>a

ans= 1 (12) (d|b)>a ans= 0

a=20; b=-2; c=0; d=’Test’;

(13) isinf(a/b) ans=014) isinf(a/c)

ans=1(15) a>b&ischar(d)ans=1(16)

isempty(c) ans= 0

2. Write a Matlab program to solve the

function1

()ln

1

y x

x

=

-

, where x is a number <1. Use an if structure to verify

that the value passed to the program is

legal. If the value of x is legal, caculate

y(x). If not ,write a suitable error

message and quit.

x=input('enter a number of x:')

if x<1

y=log(1/(1-x))

else

disp('the value of x is illegal.')

end

enter a number of x：0.5

y =

0.6931

enter a number of x：3

the value of x is illegal.

3. Write out m. file and plot the figures with grids

Assume that the complex function f(t) is defined by the equation

f(t)=(0.5-0.25i)t-1.0

Plot the amplitude and phase of function for 0 4.

t

≤≤

t=0:0.001:4;

m=sqrt((0.25.*t).^2+(0.5.*t-1).^2)

n=atan((0.25.*t)./(0.5.*t-1))

plot(t,m,'k-',t,n)

grid on

1

4. Write the Matlab statements required to calculate y(t) from the equation

22350

()350t t y t t t -+≥⎧=⎨

+<⎩

for value of t between –9 and 9 in steps of 0.5. Use loops and branches to perform this calculation. for t=-9:0.5:9 if t<0

y=3*t^2+5 else

y=-3*t^2+5 end end

y =248 y =221.7500 y = 197 y = 173.7500 y =152y =131.7500 y =113 y = 95.7500 y =80 y = 65.7500 y =53 y = 41.7500 y =32 y =23.7500 y =17 y =11.7500 y =8 y =5.7500 y =5 y =4.2500 y =2 y =-1.7500 y =-7 y =-13.7500

y=-22

y

=-31.7500

y=-43y=-55.7500 y=-70 y=-85.7500 y=-103 y=-121.7500 y =-142

y =-163.7500 y =-187 y = -211.7500 y =-238

5. Write an m.file to evalue the equation

2()32y x x x =-+for all values of x

between 0.1 and 3, in steps of 0.1. Do

this twice, once with a for loop and once with vectors. Plot the resulting function using a 4.0 thick dashed blue line.

for x=0.1:0.1:3 y=x^2-3*x+2; plot(x,y,'bo--'); hold on; end

x=0.1:0.1:3; y=x.^2-3*x+2;

plot(x,y,'b--','LineWidth',4.0) grid on