Question

f(x)= { (2x+p)/k for x=1,2,3,4,5
0 for all other values of x

given that f(2) = 1/7
find p and k

Answer 1

put x=0 in f(x) what u get ?

Answer 2

zero...?

Answer 3

yes, as f(0) = 0, u directly get p first

Answer 4

p=0?

Answer 5

f(x) =0 for any other value of x, so it will be 0 for x=0
yes! p=0 is correct :)

Answer 6

now put x=2 in f(x)

Answer 7

but the answer says p=1

Answer 8

@sauravshakya could u verify the working ?

Answer 9

is k = 28 given ?

Answer 10

no~ k=35 >.<

Answer 11

i wonder what mistake i did...

Answer 12

f(6)=0
(2*6+p)/k=0
p=-12

Answer 13

So, I think f(0)=0 cannot be done.

Answer 14

lol. so u cannot find p like that way

Answer 15

f(2)=1/7
(2*2+p)/k=1/7
28+7p=k

Answer 16

thats the only equation....

Answer 17

Yes.

Answer 18

anything else is given ? @Kystal

Answer 19

I think we are suppose to find the range of values of p and k

Answer 20

The probability distribution function, f(x), for the discrete random variable X is given by the rule:

f(x)= { (2x+p)/k for x=1,2,3,4,5
0 for all other values of x

given that f(2) = 1/7
find p and k

Answer 21

ohh!!

Answer 22

now it can be solved

Answer 23

THEN,
f(1)+f(2)+f(3)+f(4)+f(5)=1

Answer 24

^^ thats the 2nd equation

Answer 25

Yep that will give another equation and u need to solve those two equations to find p and k

Answer 26

can u find 2nd equation ?

Answer 27

erm...30p/k=1 ?

Answer 28

nopes,
did u put 1,2,3,4,5 in place of x ?
and equated to 1 ?

Answer 29

yea...?

Answer 30

(2+p+4+p+6+p+8+p+10+p)/k = 1
so the equation becomes ?

Answer 31

ah 5p~!! miscount /.\

Answer 32

got it!! thanks :)

Answer 33

so could u find correct values of p,k ?

Answer 34

p=1, k=35 XD

Answer 35

:D