Question

\[\LARGE f'(x)=x^2+3x \;\; ,\;\; f(1)=5\;\;\;\;\Longrightarrow f(2)=?\]

I need some hints

Answer 1

f(x) can be obtained by integration........then use f(1) to find value of c, then find f(2)

Answer 2

ya suroj ur correctt

Answer 3

got it?

Answer 4

\[\LARGE f(x)=\frac13 x^3 +\frac32 x^2 \;\;\;\;??\]

Answer 5

you left +C at the end

Answer 6

you need to add +C at end because it is integration

Answer 7

indefinite integration

Answer 8

ok but... I need to firnd f(2) then how??

Answer 9

on the second condition when x=1, y=5, you see , put those values and get c

Answer 10

\[\LARGE \int\limits x^2+3x \;dx = \frac13 x^3+\frac32x^2+C\]

Answer 11

put the c back on f(x) and get complete f(x) equation and then find f(2)

Answer 12

yes

Answer 13

correct

Answer 14

how can I know what the value of C is ??

Answer 15

I see it you told me before... let me try, I'll see what I can do :D

Answer 16

see second condition f(1) is 5 than mean when x=1 , y=5

Answer 17

see f(x) is what you get by integration

Answer 18

because you integrate f'(x)

Answer 19

did you catch it?

Answer 20

is C=19/6 ??

Answer 21

I'm still dizzy ! O_O

Answer 22

yes you got it

Answer 23

now put that C back in f(x)

Answer 24

got it?

Answer 25

ahh yeah... now I'll do it thank you very much ;)

Answer 26

no problem lol

Answer 27

\[f \left( x \right) = x ^{2} + 3x\]
\[f \left( 1 \right) = 1^{2} + 3 \times 1 = 5\]
\[f \left( 2 \right) = 2^{2} + 3 \times 2 = 10\]

simple.

Answer 28

@kreshnik another simple way to do something.

Answer 29

@JoshDavoll WRONG... the answer IS \[\frac{71}{6}\] !! Thanks for the help !

Answer 30

hahaha... obviously , you mus be 10-12 years ... LOL