does anyone know any trigonometry?

Question

I don't understand how to do this...

Find the domain and range of each relation, and state whether or not the relation is a function.

f(x)= x^2
f(x)= -x^2
f(x)= -x
f(x)= x^3


Heres another...

Determine which real numbers must be excluded from the domain of each function.

f(x)= x/x
g(x)= 3x/ -3x +9
f(x)= -x/ x^2 - 49
g(x)= 1/ the square root of 2x

this is really confusing.

Answer 1

did your teacher taught u to put a number instead of (x) if they taught u that as they taught me the solution is easy I'll put (3) instead of (x) :
f(3)=3^2=9
f(3)= -3^2= -9
f(3)= -3= -3
f(3)=3^3=27
well i hope u understand the method and what grade u r ?
good luck

Answer 2

The domain and range of your first 4 are all real numbers because you can substitute any number for x and get y or f(x). Any value that makes a denominator equal to zero must be excluded so here goes: 0, 3, 7 or -7, 0

Answer 3

In these functions, the domain is all possible values for x. For your first question, that would be all real numbers.
The range is the set of all the possible results after pluging in all possible values for x -- it helps if you graph the functions. E.g. the range of f(x)=x^2 is all positive numbers because it is never possible to have a negative result when you square a number.

For your second question, think of what numbers would lead to unvalid answers. e.g. f(x)=x/x What if x=0? 0/0 is undefined, therefore, 0 should be excluded from the domain.

{If that function could talk, it could ask "Pick an number, any number, except 0...." }

Answer 4

These kinds of questions are best depicted graphically for ease of understanding. Basically, think of a 2-d coordinate system with a x and y axis. Plug a couple of numbers into a function to get a basic idea of how the "curve" looks. Use graph paper if you have any. In your first function, think of f(x) as your dependent variable and x as your independent variable. Plug a bunch a values in for x, and your corresponding f(x) is your respective y position in your graph. A function is achieved if for each x value (domain), there is exactly one y value (range). Hope this helps you understand the concept a little better....good luck.

Answer 5

Trigonometry is a branch of arithmetic that study triangles and the relationships between their aspects and the angles between those aspects. Trigonometry defines the trigonometric purposes, which describe those relationships and function applicability to cyclical phenomena, inclusive of waves. the sphere developed for the duration of the 0.33 century BC as a branch of geometry used exceedingly for astronomical study.[2] it is likewise the muse of the clever artwork of surveying.

Answer 6

This website (http://mathworld.wolfram.com/) is very helpful for trig and up, especially if you're dealing with terms that you're not quite clear on.

It's a little heavy sometimes, but it can get you going in the right direction.