Math Glossary Letter I
identity
noun
an equality that holds true regardless of the values chosen for its variables
imaginary number
noun
a real number multiplied by the imaginary unit i, which is defined by its property i2 = -1.
import
noun
goods produced outside the boundaries of one country, which are then purchased by that country
imports
noun
bring (goods or services) into a country from abroad for sale
improper fraction
noun
a fraction which has its numerator value greater than the denominator. The value is greater than 1
in the black
noun
Having a positive account balance; having more money than is owed
in the red
noun
Having a negative account balance; owing more money than is available
inch
noun
a unit of length in the customary system of measurement. 1/12 of a foot.
inclusive numbers
noun
includes the first and last number and all numbers in between.
income
noun
the amount of money, property, and other transfers of value received over a set period of time in exchange for services or products.
income elasticity
noun
the quantity demanded of a particular product depends not only on its own price (see elasticity of demand) and on the price of other related products (see cross price elasticity of demand), but also on other factors such as income.

ΔD/D/ΔI/I
income elasticity of demand
noun
measures the relationship between the consumers income and the demand for a certain good.

εd = ΔD/D/ΔI/I
inconsistent
noun
When a system of equations has no solution because the lines are parallel
incremental cash flow
noun
the potential increase or decrease in a company's cash flow related to the acceptance of a new project or investment in a new asset.
independent variable
noun
Variable which determines the value of dependent variables in an equation/inequality
index
noun
an indicator, sign, or measure of something
index form
noun
A way of writing very large and very small numbers so that they are easier to understand and work with.
inequality
noun
a relation which makes a non-equal comparison between two numbers or other mathematical expressions.

>, <, ≤, ≥
inertia
noun
a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.
inflation
noun
a general increase in the prices of goods and services in an economy
initial velocity
noun
velocity at time interval t = 0
inner fence
noun
ut-off values for upper and lower outliers in a dataset
inner quartile
noun
situated between the first and third quartiles of a distribution.
innerquartile range
noun
contains the second and third quartiles, or the middle half of your data set also known as the IQR
input
noun
what goes into a function
input table
noun
a table that shows the relationship between sets of numbers that always follow the same rule.
inradius
noun
a radius of an inscribed circle or sphere
installment
noun
one of the amounts, usually equal, into which a debt is divided for payment at stated intervals over a fixed period
installment payment
noun
the option to pay for purchases over time by dividing the purchase amount into smaller equal payments
installment sales method of accounting
verb
an approach to revenue recognition in which the business owner defers gross profit on a sale until receiving cash for the sale from the buyer
integer
noun
a whole number; a number that is not a fraction

...,-5,-4,-3,-2,-1,0,1,2,3,4,5,...
integral
noun
a mathematical object that can be interpreted as an area or a generalization of area
interest
noun
payment from a borrower or deposit-taking financial institution to a lender or depositor of an amount above repayment of the principal sum, at a particular rate
interest only mortgage
noun
loan in which the borrower pays only the interest for some or all of the term, with the principal balance unchanged during the interest-only period
interest rate
noun
the proportion of a loan that is charged as interest to the borrower or proportion of principal credit given to a depositor
interest rate approximation
noun
A guess based on a formula for an interest rate
interior angles
noun
the angles between adjacent sides of a rectilinear figure
interior angles of a polygon
noun
Angles inside a polygon
Intermediate Value Theorem
noun
When we have two points connected by a continuous curve: one point below the line and the other point above the line, then there will be at least one place where the curve crosses the line.

If ƒ is a function that is continuous over the domain [a, b] and if m is a number between ƒ(a) and ƒ(b), then there is some number c between a and b such that ƒ(c) = m
internal rate of return
noun
the annual rate of growth that an investment is expected to generate
interpolation
noun
a type of estimation, a method of constructing new data points based on the range of a discrete set of known data points.
intersection
noun
the set containing all elements of A that also belong to B or equivalently, all elements of B that also belong to A.

A ∩ B
intersection of 2 lines
noun
point where 2 lines cross
interval
noun
a set of real numbers that contains all real numbers lying between any two numbers of the set
interval counting
verb
counting by a certain multiple within intervals
interval notation
noun
a method to represent an interval on a number line using subsets of the real numbers
intrinsic value
noun
measures the value of an investment based on its cash flows
inventory
noun
a complete list of items such as property, goods in stock, or the contents of a building
inventory turnover
noun
a financial ratio showing how many times a company turned over its inventory relative to its cost of goods sold (COGS) in a given period.
inverse
noun
opposite or contrary in position
investment
noun
an asset or item acquired with the goal of generating income or appreciation.
iota
noun
A letter of the greek alphabet used for math notation.

Ι  ι
irr
noun
Internal Rate of Return
irrational number
noun
a number that can NOT be expressed as the quotient or fraction p/q of two integers
irregular verb
noun
verbs that do not follow the normal patterns for tense and past participle
isosceles triangle
noun
A triangle with two equal sides and an unequal third side
iteration
noun
the process of doing something again and again, usually to improve it, or one of the times you do it: