IIT JEE , AIEEE Forum - Mathematics , Algebra - what are funstions? i don't want bookish definition ihave also got book but still i m not

magicalman

what are functions? i don't want bookish definition i have also got book but still i m not able to get it.please explain it thinking that u r explaining it to a small kid.

good answers will be surely rated

atavistic

Some condition that relates x to y.

tarinbansal

Dekh bhai small kid,
as atavistic said, function is something which relates 2 variables.
When I say 2 variables, it means that they can vary(they don't have a fixed value). Hence we have to give them values from ourselves.
Now to give them the values, we tell how one variable is related to other or how one variable changes when we change second variable.
Example y=sinx is a function.Here both x and y are variables. when we say y=sinx, we want to define that when x changes, how y changes. With the help of function we come to know that when x changes, y changes as sinx.

Hope you understood.
Rate me if it helped.

karthik2007

A function is basically a machine that churns the output according to what is fed into it.

for example, the function f(x) = 4x+5, gives the output 5 when x = 0. 9 when x = 1, and so on. The "machine" here is f(x), ie, 4x+5 in our case, and the input is x.

A function like f(x) = 2 gives the same output for whatever value of x you plug in, as the function is independent of x, ie, there is no x term there. If you are confused, write it like f(x) = 2 + 0.x, and then plug in the values for x.

You can have functions with more than one variable as well.

remember, here x is called by the name independent variable, and y which is f(x), is the dependent variable, as you can plug in any value of x that you want, but the value of y, ie, the output that you get depends on what value of x you plug in.

johri_anshuman

ek aur tarah se isko interpret kar sakte hain

A function is any curve on d graph which is not intersected by a line parallel to y axis at more than one pts.

eg, in the fig
first part mein koi bhi line parallel to the y axis does not cut the graph of the function at more than one point. (is a function)

doosre graph mein atleast a line parallel to y axis cuts the graph of function at more than 1 points. (not a function)

randomly graph pe kuch bhi draw kar de. agar a line parallel to the y axis does not cut the graph of the function at more than one point then it is a function. if not it is not a function.

rooney

In a graph, move from left to right. If the line is always moving from left to right or else not turning back towards -x direction, and is continous, it is a function. lol

magicalman

how can we say that sin , cos are functions?

rooney

As you move from left to right, the line graph line also moves from left to right always (or doesnt turn back) and is continous. So, sin n cos are functions.

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