Category "math"

PHP: How to raise number to (tiny) fractional exponent?

I'm doing a calculation in PHP using bcmath, and need to raise e by a fractional exponent. Unfortunately, bcpow() only accepts integer exponents. The exponent i

algorithm to merge two arrays into an array of all possible combinations

Example given in JavaScript: Suppose we have two arrays [0,0,0] and [1,1,1]. What's the algorithm to produce all possible ways these two arrays can be combine.

Basic example of how to do numerical integration in C++

I think most people know how to do numerical derivation in computer programming, (as limit --> 0; read: "as the limit approaches zero"). //example code for d

How to calculate the range of data type float in c++?

As we can see int has 4 byte in memory, that are 32bits, after applying range formula , we can see range of int -2147483648 to 2147483647. I have calculated the

Formula to make the ends of the arms of a spiral galaxy less dense

I want to make a spiral galaxy in Unity 3D using C# ( i use a derived logarithmic spiral ). I want to set the end of the arms less dense than the middle, but mi

Why is my rock/paper/scissors game getting the same random number for multiple function calls?

I have made a functioning (if possibly extremely verbose) game of rock/paper/scissors. If I run the game by calling the function once over and over the 'compute

Is there any way to get the step-by-step solution in SymPy?

Is there any way to get the step-by-step solution in SymPy? For example: x**2-5 = 4 step 1 x**2-5+5=4+5 step 2 : x**2=9 step 3 :x = 3 or x= -3

Trying to create point from X,Y, coordinate

I have used a formula to create an X and Y coordinate that I would like to create a point from. They are held in the attribute table, and I don't know how to us

how to get the slope of a linear regression line using c++?

I need to attain the slope of a linear regression similar to the way the Excel function in the below link is implemented: http://office.microsoft.com/en-gb/ex

Correct implementation of SI, SIS, SIR models (python)

I have created some very basic implementations of the mentioned models. However, although graphs seem to look right, the numbers don't add up to a constant. Tha

Fibonacci Numbers - Add odd numbers only - Javascript

So I am trying to develop a formula that will sum all odd Fibonacci numbers up to and including a given number. For example: Given number is 4. Then result sh

Why XOR of all subsets of a list have same frequency?

I have a list of numbers a1, a2, a3, a4, a5, ... and so on. If we find XOR of all subsets then I noticed that frequency of each distinct XOR is the same. Exam

Direct way of computing clockwise angle between 2 vectors

I want to find out the clockwise angle between 2 vectors(2D, 3D). The clasic way with the dot product gives me the inner angle(0-180 degrees) and I need to us

Rotate a 3D- Point around another one

I have a function in my program which rotates a point (x_p, y_p, z_p) around another point (x_m, y_m, z_m) by the angles w_nx and w_ny. The new coordinates are

Get current quarter in year with javascript

How can I get the current quarter we are in with javascript? I am trying to detect what quarter we are currently in, e.g. 2. EDIT And how can I count the numbe

How to find a point where a line intersects an ellipse in 2D (C#)

I need to find a point where a line (its origin is ellipse' center) intersects an ellipse in 2D... I can easily find a point on a circle, because I know an angl

What is the proper way of calculating this flow calculation in Objective C?

I'm attempting to make a iPhone flow rate calculator that uses these 3 formulas. Pressure ratio b b = p2 + 0.1 / p1 + 0.1 The C-value and B-Value are given

Integer division in Python

I'm confused about the following integer math in python: -7/3 = -3 since (-3)*3 = -9 < -7. I understand. 7/-3 = -3 I don't get how this is defined. (-3)*(-

One-to-one integer mapping function

We are using MySQL and developing an application where we'd like the ID sequence not to be publicly visible... the IDs are hardly top secret and there is no sig

Average transformation matrix for a list of transformations

I have multiple estimates for a transformation matrix, from mapping two point clouds to each other via ICP (Iterative Closest Point). How can I generate the av