# Månadsarkiv: oktober 2012

## Partial differential equations

A Partial differential equation is a differential equation that contains unknown multivariable functions and their partial derivatives. They are used to formulate problems involving functions of several variables. They can either be solved by hand or used to create a relevant computer … Läs mer

## Differential equations of the second order

Second order differential equations of the homogen type y” (x)+ a y'(x) + by(x) = 0 are possible to solve with the aid of the characteristic equation r2 + a r +b =0 If this have the roots r1 and … Läs mer

Publicerat i Calculus, matematik 4, matematik 5 | | 2 kommentarer

## Similarity

Two triangles are similar if all the corresponding angles are equal. Then the ratios of the corresponding sides to each other are the same for both triangles. In the fig above AB/BC = DE/EF or AB/DE = BC/EF. A list … Läs mer

Publicerat i Geometri, Gymnasiematematik(high school math), matematik 2c | | Lämna en kommentar

## How to draw exceldiagrams

My instruction video concerning drawing diagrams in Excel: http://www.youtube.com/watch?v=NSO04ELH4Qg

Publicerat i Uncategorized | Lämna en kommentar

## Separable variables

Differential equations of the form dy/dx = – P(x)/Q(y) then it is possible to separate the variables Q(y)dy = – P(x) dx → Q(y) dy + P(x) dx = 0 Ex y´+ sinx y = 0 y´ = -sinx y dy/y … Läs mer

## Differential equations

An equation containing the derivative of a function is called a differential equation. Depending on the order of the derivatives it is of the first, second or higher order. The simplest differential equation is an ordinary linear homogenous differential equation of the first order: y’ + … Läs mer

Publicerat i Calculus, Gymnasiematematik(high school math), Uncategorized | | 1 kommentar

## Cylindrical coordinates

Cylindrical coordinates can be considered as a hybrid between spherical coordinates and rectangular coordinates. The coordinates of a point is given by the angle between the projection of the point in the xy-plame Φ and two distances: the distance from the … Läs mer

Publicerat i Geometri, Uncategorized | | Lämna en kommentar

## Dimensions and different coordinate sytems

The number of figures necessary for specifying the position of a point is called the dimension of the space. For a two dimensional space it is sufficient to use two numbers (x, y) : one specifying the position on a … Läs mer

Publicerat i Algebra, Geometri, matematik 1c, Uncategorized | | 1 kommentar