# Alevel math A set of curves that each pass through the origin have equations y=f1(x),

Watch
Announcements
#1
A set of curves that each pass through the origin have equations y=f1(x),f2(x) and f3(x) where f 'n(x)=fn-1(x) and f1(x) =x^2.

a) find f2(x), f3(x)
b)suggest an expression for fn(x)
thanks
0
4 days ago
#2
(Original post by interlanken-fall)
A set of curves that each pass through the origin have equations y=f1(x),f2(x) and f3(x) where f 'n(x)=fn-1(x) and f1(x) =x^2.

a) find f2(x), f3(x)
b)suggest an expression for fn(x)
thanks
Have you tried integration?
0
#3
(Original post by mqb2766)
Have you tried integration?
what do we integrate and why do we integrate ?
0
4 days ago
#4
(Original post by interlanken-fall)
what do we integrate and why do we integrate ?
Ghostwalker explained it fairly clearly on the other thread.
You know the derivative, so integrate to get the curve.
0
#5
so the
derivative is the rate of change, and so because its x2 then we integrate it to get the equation from it? how do we do that for f2(x) and f3(x) do we multiply by 3 or? do we integrate evern further
(Original post by mqb2766)
Ghostwalker explained it fairly clearly on the other thread.
You know the derivative, so integrate to get the curve.
0
4 days ago
#6
(Original post by interlanken-fall)
so the
derivative is the rate of change, and so because its x2 then we integrate it to get the equation from it? how do we do that for f2(x) and f3(x) do we multiply by 3 or? do we integrate evern further
Have you worked out f2 by integrating f1?
If so, what did you get?
Last edited by mqb2766; 4 days ago
0
#7
(Original post by mqb2766)
Have you worked out f2 by integrating f1?
If so, what did you get?
by integrating X2 i get = x^3/3
0
#8
(Original post by interlanken-fall)
by integrating X2 i get = x^3/3
and for f3(x) I integrate again = 1X^4/12
0
#9
I just dont understand why we integrate
0
4 days ago
#10
(Original post by interlanken-fall)
I just dont understand why we integrate
Because you're told the
* Derivative of f2 is f1. So integrate (inverse of derivative) to get f2.
* Derivative of f3 is f2, so integrate (inverse of derivative) to get f3
..... And so on ...
1
#11
(Original post by mqb2766)
Because you're told the
* Derivative of f2 is f1. So integrate (inverse of derivative) to get f2.
* Derivative of f3 is f2, so integrate (inverse of derivative) to get f3
..... And so on ...
omg you are amazing and a genius thank you!!!!!!!
1
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

Yes (489)
51.86%
No (454)
48.14%