Question

Are these expressions polynomial functions? Why or why not? 1) 3x^8-6x^2+(pi)(times)x 2) 3x^8-6ix^2+(pi)(times)x

Answer 1

they are not functions because they don't show any relations between x and y

Answer 2

So what would be an example of a polynomial function?

Answer 3

both of them are polynomial functions.

Answer 4

Thank you! I thought so..... I wasn't sure about #2 because it had two variables

Answer 5

@chenna, why r they polynomial functions

Answer 6

they r polynomial expressions, not functions

Answer 7

It says,"Cross out the expressions that are not polynomial functions."

Answer 8

and what exactly does that mean?

Answer 9

what do you mean by ' a function' ? define a function.

Answer 10

They both are polynomial functions. function is a mapping, i.e. which maps values from one set to another set. for ex. y = 2*x, z=log(x) etc.
sometimes we write y=2*x and sometimes f(x) =2*x. both are same. there is no difference. And the functions given above are polynomials. Hence they are polynomial functions.

Answer 11

So can a polynomial function have more than one variable?

Answer 12

what other variable do you see, apart from 'x' in the above equations ?

Answer 13

i

Answer 14

yes, a function is a mapping. But in that "function" I see no other set. I only see x as a variable

Answer 15

a function is say y=x. It is a relation that says that for all values of x, y is equal to that x. It maps x to y

Answer 16

So then what's the "i" for in the second option?

Answer 17

it can be the complex root, the square root of -1

Answer 18

'i' is not a variable. its just another constant. To explain you better,
consider the polynomial \[x^{2}+1\]. = \[x ^{2}-i ^{2}\].
First function maps x in to space of real values and 2nd function maps x into complex space.