What is Algebra ?

The equation x^2 - x - 3 is called a quadratic trinomial.

Quadratic equations are commonly encountered in algebra I and II; their graph, known as a parabola,

describes the arc traced by a projectile fired into the air.

Exponential equations are distinguished from polynomials in that they have variable terms in the exponents.

An example of an exponential equation is y = 3^(x - 4) + 6.

Exponential functions are classified as exponential growth if the independent variable has a positive coefficient and exponential decay if it has a negative coefficient.

Exponential growth equations are used to describe the spread

populations and diseases as well as financial concepts such as compound interest (the formula for compound interest is Pe^(rt), where P is the principal, r is the interest rate and t is the amount of time). Exponential decay equations describe phenomena such as radioactive decay.

Rational Equations
Trigonometric equations contain the trigonometric functions sin, cos, tan, sec, csc and cot.

Trigonometric functions describe the ratio between two sides of a right triangle, taking the angle measure as the input or independent variable and the ratio as the output or dependent variable.

For example, y = sin x describes the ratio of a right triangle's opposite side to its hypotenuse for an angle of measure x.

Trigonometric functions are distinct in that they are periodic, meaning the graph repeats after a certain amount of time.

The graph of a standard sine wave has a period of 360 degrees.