matlab编程

E304731541

d=sym(3*x^3-2*x+1);
diff(d,2)
* k: W8 V2 `% _1 }  Iezplot('cos(x)',[0,pi])//4.2
ezplot('(cos(t))^3','(sin(t))^3',[0,2*pi])//4.3
/ o1 i' S4 z% R  S0 U2 M. rezplot('exp(x)+sin(x*y)',[-2,0.5,0,2])//4.4
  h; ]. O1 y( f fminbnd('x+3*(x^2+cos(x))',-1,1)  //直接求
+ s$ o* s& h" ^ f=sym('x+3*(x^2+cos(x))');//由导数为零来求解
" N; Z9 L( A( E9 j9 S  ff=solve(diff(f));
! Y4 U5 i& m) c) i; [subs(f,x,ff),subs(f,x,-1),subs(f,x,-1)
) G- v. S; z' b; y3 P, k$ asyms x;
* c8 M, A; m, K7 Z+ `int(1/sin(x)^2*cos(x)^2)
syms x z;
int(x/(1+z^2),x)
A=[1,2,3;4,5,6;7,8,9;10,11,12]
A =
     1     2     3
     4     5     6
     7     8     9
: c8 M- @, Z( U6 K- l' h    10    11    12
B=[0,1,1;2,2,1;1,1,1];
A*B
5 h! ?  M4 M9 ^9 y/ S& MA^3//错误，矩阵的幂必须矩阵的行列相同才行
rref(A)
x=linspace(0,2*pi,30);
0 C/ B, E) [) L/ Ay=sin(x);
z=cos(x);
plot(x,y,'r',x,z,'pg')
0 `1 ^4 D1 m. s7 Q! Mx=linspace(0,2*pi,30);
# e2 V8 r- z/ ?9 t6 ry=sin(x);
z=cos(x);
, m" Z, ]  L: S  f3 ~  o1 J/ Sxlabel('自变量x')
ylabel('函数y')
" K5 H3 ^5 r4 K6 T' @title('示意图')
plot(x,y,'r',x,z,'pg'),grid on;
. C- l: _: Q3 `5 Bx=linspace(0,2*pi,30);
y=sin(x);
! t2 k2 U* [; Mz=cos(x);
plot(x,z,'pg');
0 U5 T+ s% w: Dhold on;
plot(x,y,'r')
x=linspace(0,2*pi,100);
. ?- O) o  X+ O5 W8 g  e1 U# [' Ny=sin(x);
z=cos(x);
$ ~3 \- w7 u1 v+ i/ tplot(x,y);
title('sin(x)')
pause;
3 Z; f( P5 K9 _  _. O2 |! l2 M% qfigure(2);
plot(x,z,'pg');
5 d3 F5 {6 x2 s' U/ i, \- y* btitle('cos(x)')
x=linspace(0,2*pi,30);
# x4 ?/ O* J7 Hy=sin(x);
1 _- g9 A% M* ], ]  g  Y8 {plot(x,y,'r');
7 Q" g1 t+ u" i7 Wzoom on
p=[1 -4 9 -10];
r=roots(p)//次数小于等于4，若大于4则用该命令不一定能求出所有根的准确形式。
r=solve('x^3-4*x^2+9*x-10=0')//简单方法
r=solve('x^2-a*x-4*b=0','x')
d=solve('p*sin(x)-r','x')
+ ]7 U' [$ ~# s. }r=fzero('x-(cos(x))^2',1)//其中必须输入的是方程对应的函数名
' U  \) d6 g, q0 w[x,y]=solve('x+y=1','x-11*y=5','x','y')

mrx

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qingqing20072

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qingqing20072

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qingqing20072

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xxj198712

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zhula

2# mrx
谢谢啊！！

zhula

2# mrx
2 h& z: ^2 f  D. w% B: j太感谢了

zhula

2# mrx
% u; j& M" O* B& v+ ?* Z+ U8 ^最近在做有关促销的文章，可以借鉴，３Ｑ

byit

Thanks you~~