Breve digressão pelo MATLABbaseada em exemplos
Hugo Alonso
Universidade de Aveiro2013/2014
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MATLAB = MATrix LABoratory
Linguagem de computação técnica + ambiente interactivo
Funcionalidades:computação numéricacomputação simbólicacriação, visualização e manipulação de gráficosprogramação...
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>> a=1/4, b=pi; c=0a =0.2500c =0
>> bb =3.1416
>> format long
>> bb =3.141592653589793
>> format short
>> bb =3.1416
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>> help sqrtSQRT Square root.SQRT(X) is the square root of the elements of X. Complexresults are produced if X is not positive.
See also sqrtm, realsqrt, hypot.
Overloaded methods:distributed/sqrtcodistributed/sqrtsym/sqrt
Reference page in Help browserdoc sqrt
>> sqrt(a)ans =0.5000
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>> lookfor tangentacot - Inverse cotangent, result in radian.acotd - Inverse cotangent, result in degrees.acoth - Inverse hyperbolic cotangent.atan - Inverse tangent, result in radians.atan2 - Four quadrant inverse tangent.atand - Inverse tangent, result in degrees.atanh - Inverse hyperbolic tangent.cot - Cotangent of argument in radians.cotd - Cotangent of argument in degrees.coth - Hyperbolic cotangent.tan - Tangent of argument in radians.tand - Tangent of argument in degrees.tanh - Hyperbolic tangent.tansig - Hyperbolic tangent sigmoid transfer function.dtansig - Hyperbolic tangent sigmoid transfer derivative function.
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>> help tanTAN Tangent of argument in radians.TAN(X) is the tangent of the elements of X.
See also atan, tand, atan2.
Overloaded methods:distributed/tancodistributed/tansym/tan
Reference page in Help browser
doc tan
>> d=tan(b/4)d =1.0000
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>> whoYour variables are:a ans b c d
>> ansans =0.5000
>> clear a
>> whoYour variables are:ans b c d
>> clear
>> who
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>> diary aula1.txt>> f=inline(’exp(x-1)*sqrt(x)/(1+x^2)’)f =Inline function: f(x) = exp(x-1)*sqrt(x)/(1+x^2)>> f(0),f(1),f(2)ans =0ans =0.5000ans =0.7688>> f=inline(’exp(x-1).*sqrt(x)./(1+x.^2)’)f =Inline function: f(x) = exp(x-1).*sqrt(x)./(1+x.^2)>> f([0 1 2])ans =0 0.5000 0.7688>> diary off
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>> xx=linspace(0,2,1000);
>> plot(xx,f(xx),’k-’,xx,f(xx)+1,’r-’)
>> xlabel(’x’),ylabel(’y’),legend(’f(x)’,’f(x)+1’)
>> grid on
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
x
y
f(x)
f(x)+1
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>> f(x)??? Undefined function or variable ’x’.
>> syms x real
>> f(x)ans =(x^(1/2)*exp(x - 1))/(x^2 + 1)
>> diff(f(x),x)ans =exp(x - 1)/(2*x^(1/2)*(x^2 + 1)) + (x^(1/2)*exp(x - 1))/(x^2 + 1) -(2*x^(3/2)*exp(x - 1))/(x^2 + 1)^2
>> int(f(x),x,0,2)Warning: Explicit integral could not be found.ans =int((x^(1/2)*exp(x - 1))/(x^2 + 1), x = 0..2)
>> quad(f,0,2)ans =0.9462
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>> clear, clc
>> soma=0;
>> for i=1:10,soma=soma+i;end;
>> somasoma =55
>> clear soma
>> i=1:10;
>> soma=sum(i)soma =55
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>> clear
>> u=[1 2 3]u =1 2 3
>> v=[1 2 1]v =1 2 1
>> w=[1 0 1]’w =101
>> whosName Size Bytes Class Attributes
u 1x3 24 doublev 1x3 24 doublew 3x1 24 double
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>> [u v]ans =1 2 3 1 2 1
>> [u;v]ans =1 2 31 2 1
>> [u’ w]ans =1 12 03 1
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>> u+vans =2 4 4
>> u*v??? Error using ==> mtimesInner matrix dimensions must agree.
>> u*wans =4
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>> y(1)ans =1
>> y(1)=0y =0 4 3
>> y([1 3])ans =0 3
>> y([1 3])=[-1 -2]y =-1 4 -2
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>> clear
>> A=[1 2;3 4], B=[1 1 0;0 1 0]A =1 23 4B =1 1 00 1 0
>> whosName Size Bytes Class Attributes
A 2x2 32 doubleB 2x3 48 double
>> A*Bans =1 3 03 7 0
>> B*A??? Error using ==> mtimesInner matrix dimensions must agree.
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>> A*Aans =
7 1015 22
>> A^2ans =
7 1015 22
>> A.*Aans =1 49 16
>> A.^2ans =1 49 16
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>> 2*Aans =2 46 8
>> 1+Aans =2 34 5
>> sqrt(A)ans =1.0000 1.41421.7321 2.0000
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>> A(2,1)ans =3
>> A(2,1)=0A =1 20 4
>> B(1,1:3)ans =1 1 0
>> B(1,:)ans =1 1 0
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>> B(1:2,1:2)ans =1 10 1
>> B(:,1:2)ans =1 10 1
>> B(:,[1 3])ans =1 00 0
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Consultar Moodle para mais material!
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