Question

Find the following values for the given functions.

f(x) = x + 5, g(x) = x^2

(f+g)(5)=..?

Answer 1

my brother..... uchiha

Answer 2

well, (f+g)(x) = f(x) + g(x)

Answer 3

now can u do the rest?

Answer 4

hwahhaha.. lol @driftracer305 .. hwaha.. @PFEH.1999 so i will first substitute the 5 to f(x) and g(x) before i perform the solution..?

Answer 5

k first always plug in given value like 5 in the last letter of equation like you have g....then plug the result as a value of x for f(x)

Answer 6

ok, first let's see what's (f+g)(x)
f(x) + g(x) = x^2 + x + 5

Answer 7

and then you can find (f+g)(x) ;)

Answer 8

oh.. so i will make it as x^2 + x+ 5 before doing the substituting the 5..?

Answer 9

sorry wrong grammar.. hahah

Answer 10

i told you to do this because it would help you to understand but you can first plug 5 too ;)

Answer 11

i always do it as g(5) = 5^2 =25........... now you have f(25) = 25 + 5 =30

Answer 12

you can say what is f(5) and g(5) and then find f(5) +g(5) ;)

Answer 13

addition is linear operator so \((f+g)(x)=f(x)+g(x)\)

Answer 14

yes @zzr0ck3r but i told this ;)

Answer 15

ahh.. yeah.. but will it be the same if i add it first before substituting or substitute first before add.?

Answer 16

yes ;)

Answer 17

ie
plug in after = plug in before
:)

Answer 18

nope, same thing

Answer 19

thats the cool part!

Answer 20

i dont knw what u jus said @russeldano ........ but like i said... plug and evaluate............
KEEP Calm and be an Uchiha....... lol

Answer 21

@driftracer305 yeah.. i was thinking about that but i wasnt sure so i asked.. hahah

Answer 22

@russeldano try it both ways to convince yourself

Answer 23

yea...... math has one answer but thousand ways to get it..... so do what u fell good with

Answer 24

nah, once you feel good, try it different ways. but do it the one way on the test:)

Answer 25

@zzr0ck3r woah.. haha.. its the same.. awesome.. hwahh.. i get it now.. hwahha.. @driftracer305 yeah.. thats why i like math.. but sometimes i forgot someways to do the equation.. hwhaha.. tnx @zzr0ck3r , @PFEH.1999 , @driftracer305 .. haha..

Answer 26

yes,after solving a problem . try other ways . it would help u to understand questions better and solve harder one ;)
you're welcome :)

Answer 27

last question.. is this correct..? (fg)(5)= f(5)*g(5)..? haha...

Answer 28

lol...... u could have just used your sharingan @russeldano ...... if you know wat i mean.. ;)

Answer 29

tes;)

Answer 30

hwahaha.. @driftracer305 i guess i know what u mean there.. hwahha

Answer 31

ohh yea.. it is right

Answer 32

(f+g)(x) = f(x) + g(x)
(fg)(x) = f(x) . g(x)
(f/g)(x) = f(x) / g(x)

Answer 33

and (f-g)(x) = f(x) - g(x) too ;)

Answer 34

ahh.. got it know.. but can i ask again a question.. will i perform this or just substitute..?

Find f (a), f (a + h), and the difference quotient for the function given below, where h not equal to 0.
f (x) = 4x2 + 7

f(a+h)-f(a)/h =..?

Answer 35

well,ok.let's start with this one:
f(a) = a^2 + a
and then f(a+h) = ?

let's imagine a+h = y
so we should find f(y)
f(y) = y^2 + y
and then y = a+h
so f(a+h) = (a+h)^2 + (a+h)
;)
got it?

Answer 36

didnt get the part where f(a) = a^2 + a..? where did that came from..?

Answer 37

it is only an example ;)

Answer 38

i wanted you to know this and then solve that question

Answer 39

ooopss sorry f (x) = 4x2 + 7 it was suppose to be f (x) = 4x^2 + 7 haha ahh.. ok got it..

Answer 40

and now can you solve it yourself ?

Answer 41

ok ok got it.. then.. haha

Answer 42

nice :)

Answer 43

wait i will show you what is my answer ok..?

Answer 44

(4(a+h)^2 + 7)-(4a^2 +7) / h..?? im stuck at here.. dont know what is the next move..? haha..

Answer 45

it's correct :)

Answer 46

thats the final answer..? no need to do any simplification..?

Answer 47

no,the question wants us f(a+h)-f(a)/h and u found it ;)
any other questions?

Answer 48

ahh.. ok.. no need to simplify.. just follow the direction as is.. haha.. tnx.. you've really helped me.. hahah

Answer 49

you're welcome ;) functions are really interesting