tri.js

/**
	Pair Programming Practice. Submit a link to your gist here when you are done:
	https://goo.gl/forms/mPumIHpIKF3W1gjt2
*/

/**
	EXERCISE ONE
	What is wrong with the following definitions of square? Write a sentence or two describing the issue(s); then, 
	try copying the erroneous examples into a console one-at-a-time and observing the error(s) generated (you may 
	have to attempt to invoke the functions to see the error). What errors are produced (if any) for each erroneous 
	version? Do the errors make sense?
*/

function square(monkey) {
  return x * x;
}
//undefined
//change monkey to x

function square(5) {
  return 5 * 5;
}
//Uncaught SyntaxError: Unexpected number
//parameter name can'tbe a number

function square("x") {
  return "x" * "x";
}
//Uncaught SyntaxError: Unexpected string
//can't multiply a string

/**
	EXERCISE TWO
	Fix the invalid syntax in the following functions
*/

function square1(x) {
  return x * x;
}

function square2 (x) {
  return x * x;
}

function square3 (x) {
  return x * x;
}

/**
	EXERCISE THREE
	The following functions exhibit poor style -- fix these issues. Use slide 63 from W1D1 Lecture as the "right" way to do it.
	https://docs.google.com/presentation/d/1UD_oVyx8O-ELxk5pmsMDpCLptb7vpYrANCR2VA4_j2w/edit?usp=sharing
*/

function square(x) {
	return x * x;
}

function square(x) {
	return x * x;
}

function square(x) {
	return x * x;
}

/**
	EXERCISE FOUR
	Complete the function 'cube' that returns the cube of x:
*/

function cube(x) {
 // your code here
 	return x * x * x;
}

/**
	EXERCISE FIVE
	Complete the function 'fullName' that should take two parameters, 'firstName' and 'lastName', and returns the 
	'firstName' and 'lastName' concatenated together with a space in between.
*/

// don't forget the parameters!
function fullName(firstName, lastName) {
 // your code here
 	return firstName + " " + lastName;
}
fullName("John", "Doe") // => "John Doe"

/**
	EXERCISE SIX
	Write a function 'average' that takes two numbers as input (parameters), and returns the average of those numbers.
*/
function average(num1, num2){
	return (num1 + num2) / 2;
}

/**
	EXERCISE SEVEN
	Write a function 'greeter' that takes a name as an argument and greets that name by returning something along the 
	lines of "Hello, <name>!"
*/

function greeter(name){
	return "Hello, " + name + "!";
}

/**
	EXERCISE EIGHT
	Compound interest can be calculated with the formula found here: 
	https://en.wikipedia.org/wiki/Compound_interest#Calculation_of_compound_interest
	F: future value
	P: present value
	i: nominal interest rate
	n: compounding frequency
	t: time
	Write a function 'futureValue' that can be used to calculate the future value of a quantity of money using 
	compound interest.
	Use the function to calculate what the future value of $1700 (P = 1700) deposited in a bank that pays an 
	annual interest rate of 4.7% (i = 0.047), compounded quarterly (n = 4) after 6 years (t = 6) (you can 
	use Math.pow to do exponentiation).
*/

function futureValue(P, i, n, t){
	return P * Math.pow(1 + i/n, n*t);
}

futureValue(1700, .047, 4, 6);

/**
	EXERCISE NINE
	Write your own square-root function called sqrt that accepts a number parameter and returns an approximate 
	square root. Square-root approximations make use of averages. Be sure to use the average function you 
	previously wrote. The first version of your square root function should perform no more than 3 successive 
	averages. Use this resource in case you're not familiar with ancient Babylonian algorithms:
	http://www.had2know.com/academics/babylonian-algorithm-square-root.html
*/

function average(num1, num2){
	return (num1 + num2) / 2;
}

function sqrt(number){
	var newNumber1 = average(number, number / 2);
	var newNumber2 = average()
}