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Symbolic Mathematic examples in Mathematica


x = 3; y = 5;
x + y


8

Differentiation

Clear[] variables in case they have values left over from earlier.

Clear[a, b, x];
expr = 2 a x + b;
D[expr, x]


2 a

Integration

	Integrate[expr, x]

2
b x + a x

Matrix and Vector Operations


Clear[a, b, c, d, x, y];

(* matrix *)
m = {{a, b}, {c, d}}


{{a, b}, {c, d}}


(* vector *)
v = {x, y}


{x, y}


(* constant times matrix *)
k m


{{a k, b k}, {c k, d k}}


(* square each element of m *)
m^2


2 2 2 2
{{a , b }, {c , d }}


(* matrix multiplication *)
m . m


2
{{a + b c, a b + b d},

2
{a c + c d, b c + d }}


(* matrix times vector, v acts as column vector *)
m . v


{a x + b y, c x + d y}


(* vector times matrix, v acts as row vector *)
v . m


{a x + c y, b x + d y}



(* transpose matrix *)
Transpose[m]


{{a, c}, {b, d}}

Solving Equations


Clear[x, y]



Solve[{x + y == 10, 2x - y == 5}, {x, y}]


{{x -> 5, y -> 5}}


Solve[{a x^2 + b x + c == 0}, x]


2
-b - Sqrt[b - 4 a c]
{{x -> ---------------------},
2 a

2
-b + Sqrt[b - 4 a c]
{x -> ---------------------}}
2 a


a = 1; b = 5; c = 4;
Solve[{a x^2 + b x + c == 0}, x]


{{x -> -4}, {x -> -1}}


b = 10; c = 9;
Solve[{a x^2 + b x + c == 0}, x]


{{x -> -9}, {x -> -1}}


c = 8;
Solve[{a x^2 + b x + c == 0}, x]


{{x -> -5 - Sqrt[17]},

{x -> -5 + Sqrt[17]}}


N[%]


{{x -> -9.12311},

{x -> -0.876894}}

Last Modified: Dec 19, 2016 11:12 am US/Eastern
Created: May 10, 2007 12:51 pm GMT-4 by admin
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