domingo, 23 de junio de 2013

Excelente calculadora cientifica online con operaciones con numeros complejos

Funciona con una pila y es muy buena para numeros complejos

tener en cuenta que para ingresar un angulo es con el coton cis, el cual equivale al simbolo.
(240cis(75*pi/180))
esto en radiantes: 240cis1.309

se deben considerar angulos en rads

Ejemplo de operaciones con numeros complejos:
(30.754+207.428i)/(-3+51i)

esto da como resultado: 4.105cis(-0.206)

y con el boton prefs se cambia a rectangulares o cartesianas y a polares o polar
al cambiar a cartesian el resultado es:

(4.018-0.839i)

el redondeo se hace a 3 decimales desde prefs

http://www.alcula.com/calculators/scientific-calculator/


Online Scientific Calculator

Welcome to the new Online Scientific Calculator for Algebra from Alcula.

For help refer to the Instruction manual and to the Online Scientific Calculator blog entries.
This is a formula calculator. Enter your expressions in the same order as you would write them on paper. Then press '=' to display the result.
Use parenthesis to alter the order of operations or to specify function parameters.
Example of a valid expression: (-3+sqrt(16/4))/4
Results are displayed as fractions when possible, as well as in their floating point approximation.
This calculator supports the following operators, functions and constants:

Operators

  • + - * /: Addition, subtraction, multiplication and division
  • cis: Use for entering complex numbers in polar form (See Complex Numbers)

Trigonometric functions

  • sin: Sine
  • asin: Inverse sine (sin-1)
  • sinh: Hyperbolic sine
  • cos: Cosine
  • acos: Inverse cosine (cos-1)
  • cosh: Hyperbolic cosine
  • tan: Tangent
  • atan: Inverse tangent (tan-1)

Constants

  • e: The constant e
  • i: The imaginary unit (See Complex Numbers for more information)
  • pi: The constant PI (&pi)

Statistics functions

  • !: Factorial
  • perm: Permutations
  • comb: Combinations

Logarithms

  • ln: Natural Logarithm (base e)
  • log: Logarithm base 10

Other functions

  • abs: The absolute value
  • ans: The result of a previous expression
  • gcd: Greatest Commmon Divisor (see GCD)
  • int: The integer portion of a number (see INT)
  • lcm: Least common multiple (See LCM for more info)
  • rand: Returns a random number between 0 and 1 (see rand and how to use the random function for information on how to use this function)
  • round: Rounds a number to its closest integer (See round for examples)
  • sqrt: Square root
This calculator allows you to define your own functions to use in expressions. To define a function type type it in this format: <function name>(<arguments separated by commas>)=<body>. Example: area(x,y)=x*y .
You can also select to display the results in a different notation. Choose between fixed, floating point, scientific or engineering notation. See calculator notation for more information.
You can type your expressions directly in the calculator input field or use the online keyboard.

sábado, 22 de junio de 2013

Talk english, speak englis, improve your pronunciation

EL metodo que reomiendo:
Escuchar las frases
Entenderlas
Repetirlas
Grabarlas (con audacity o grabadora de windows)
Escucharse a si mismo

Para mejorar la pronunciaciòn les dejo este link

www.talkenglish.com

En el encuentran sentencias necesarias como


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