agranado2k / bi-calculator

Calculator for Polynomial derivation

How to configure

Clone the repo and inside the project folder execute the command bundle

if the bundle gem is not installed you can install it executing the command: gem install bundle

How to test

Execute the command: bundle exec rspec

After that you can see the coverage open the index.html file on coverage folder.

How to execute

Execute the command to start the server bundle exec rails s

And you can test send GET request as the example

curl -i -X GET 'http://localhost:3000/differentiate/4/3/0/1' or curl -i -X GET 'http://localhost:3000/differentiate/4/-5/0/1

###Requirements:

The task is:

Write a web service in ruby that is backed by a class, Calculator that can do mathematical differentiation of polynomials:

DEFINITIONS

1. A polynomial is a function of the form f(x) = a*x^b + ... where a is known as a coefficient, and b is called the exponent.
2. If you have a function f(x), then its derivative is denoted by f'(x)
3. Differentiating, or taking the derivate of a polynomial follows a simple formula: f'(x) = abx^(b-1)
4. Differentating sums of polynomials follows the rule: If f(x) = g(x) + h(x) then f'(x) = g'(x) + h'(x)

EXAMPLES For example, x^2 as input would give 2x^1 as output 3x^2+x+1 would give 6x+1

Input: GET /differentiate/3/2/1 would represent -> 3x^2+2x+1 Output would be: 6x+2

And for input: GET /differentiate/4/3/2/1 would represent -> 4x^3+3x^2+2x+1 Output would be: 12x^2+6x+2

A request to GET /differentiate/4/3/0/1 would represent the equation 4x^3+3x^2+0+1 and the output you should return ought to be 12x^2+6x A request to GET /differentiate/4/-5/0/1 would represent the equation 4x^3-5x^2+0+1 and the output you should return ought to be 12x^2-10x

As you may have guessed by each exponent is represented by its order in the path component, and its corresponding exponent is represented by the value of the path exponent.

More information:

1. You may use google/wikipedia or whichever resources you would normally make use of to solve this problem.
2. Please make sure there is test coverage for requests and method, and put it on a bitbucket/github that you share with me, username: cfeckardt
3. Please use only 90 min to complete the task. We do not expect a full solution to the problem, and you will not be evaluated on whether you completed the problem or not, but rather on the approach you take to solve the problem.
4. I will schedule a short call with you after submission, so that we can go over it together.
5. If you have a any questions or need clarifications, feel free to reach out per e-mail, phone or keybase (cfeckardt)