Question

f(x) = x^2 [x]
then f`(3/2) = ?

Answer 1

what is the derivative of \(x^2 x\)?

Answer 2

or better yet, can you simplify \(x^2x\)?

Answer 3

I think [x] is supposed to be the floor function

Answer 4

oh uhm then I am no help unfortunately... I don't even think that has a derivative does it? It's no where near continuous

Answer 5

since [x] = 1 when 1 <= x < 2

x^2 [x] = x^2, for 1 <= x < 2

so, f'(x) = 2x = 2(3/2) = 3

Answer 6

ahhh if you define it piecewise it does

Answer 7

yes :)

Answer 8

Idk I guess we shall see when @hamoody1996 responds

Answer 9

[x] should be the int function?

Answer 10

so f'(x)=floor(x)*2x when x is not equal to an integer i believe

Answer 11

but anyways we don't know if it's the floor since they have not responded, and [] are not how you represent floor, floor won't have the toppart soo..... waiting on a response......

Answer 12

it looks like it can mean either http://mathworld.wolfram.com/NearestIntegerFunction.html

Answer 13

depending on what the person who wrote it meant

Answer 14

floor=int

Answer 15

sort of

Answer 16

no i was talking about the notation

Answer 17

it says in that link [ ] could mean int or floor

Answer 18

i wasn't saying they are equal

Answer 19

oh

Answer 20

I believe the convention is that [x] is the floor function, not the ceiling function.

Answer 21

we still don't know if that is even what they were asking haha

Answer 22

they're offline, guess we shall never know

Answer 23

If anything, it should be the floor function or integer part.

Answer 24

as far as I know, [x] = int[x] = floor(x).

Answer 25

actually [x] is the floor function
and the choices were 1 ,2 , 3 , not found
thanks yall