Question

Function Notation problem



Let f(x)=2x+1.
Is f(3+1)=f(3)+f(1)?
please answer it ????
thank you

Answer 1

No

Answer 2

See: for any function f(x), f(a+b) means that in the formula of f(x), put x = a+b.

Answer 3

For example;


let, f(x) = 5x + 4

Then, f(2) = 5*2 + 4 = 14

f(5) = 5*5 + 4 = 29

f(2+5) = f(7) = 5*7 + 4 = 39 \(\ne\) f(5)+f(2)

Answer 4

how to answer it

Answer 5

You can answer it in this way:

First calculate f(3+2) i.e. f(5), then calculate f(3) and f(2), then show that f(5) \(\ne\) f(2) + f(3).

Answer 6

As I did in above example.

Answer 7

my question is a example

Answer 8

how to answer it
this my question??

Answer 9

Let f(x)=2x+1.
Is f(3+1)=f(3)+f(1)?

Answer 10

Okay here is the detailed solution.

Answer 11

Since, f(x) = 2x + 1, thus,

f(3) = 2*3 + 1 = 6 + 1 = 7 ---------(1)

f(1) = 2*1 + 1 = 2 + 1 = 3 ---------(2)

f(3+1) = f(4) = 2*4 + 1 = 8 + 1 = 9 ---------(3)

Now, f(3) + f(1) = 7 + 3 = 10 ------------ (4)

Clearly,

\[\large{f(3+1) \ne f(3) + f(1)}\]

Answer 12

Do you get this ?

Answer 13

yes thanks

Answer 14

No Problem. :)

Answer 15

wait

Answer 16

last

Answer 17

let f(x)= \[\sqrt{x}\]
Is f(3+1)=f(3)+f(1)?