Question

Can someone solve this please?

the points (2,6) and (3,18) lie on the curve y=ax^n
use logarithms to find the values of a and n, giving your answers correct to 2d.p.

thanks :)

Answer 1

6 = a(2^n) ------> a = 6/2^n
18 = a(3^n)-------> 18 = 6(3^n)/(2^n)---->3 = 3^n/2^n

Answer 2

3 = (3/2)^n

Answer 3

i dont know what you did :(

Answer 4

how did you get 3=(3/2)^n?

Answer 5

because 18 = 6(3/2)^n, divide both sides by 6

Answer 6

ok :)

Answer 7

but i need a number with 2dp
:S

Answer 8

okay. so we have 3 = (3/2)^n
take log on both sides
log 3 = log(3/2)^n -------> log 3 = n log(3/2) ----> n = log 3/ log(3/2)
use calculator to find the value of n to 2 dp

Answer 9

2.71!!!
YAYA!
thanks ill give u a medal :)

Answer 10

you are welcome.

Answer 11

use n to find a by substituting in one of the equations.

Answer 12

oh :(
i thought that the qs ended
ill do that now then :)

Answer 13

ok I got n=log(1/3) /log(2/3)
maybe I made a mistake

Answer 14

:S

Answer 15

oh wait it might be the same thing lol

Answer 16

ya lol

Answer 17

there are so many properties with log

Answer 18

the reason they are the same is :
log(1/3) /log(2/3)=[log1-log3]/[log2-log3]=[0-log3]/[(-1)(log3-log2)]=log3/[log3/2]

Answer 19

wow, it looks like a sentence without any words XD

Answer 20

its not hard to understand if you think about it, Miss.

Answer 21

n=ln3\(ln3/2) et a=6/[2^(ln3/2)]

Answer 22

i dont actually understand it
it looks like random equations put together :p

Answer 23

okay. I hope for your sake that you are not taking math as a major course then :)

Answer 24

no, really wanna drop it next year.
its way too hard
i cant manage it :(

Answer 25

yes, some people are good at certain things, others are good at other things.