How do i solve this? please help?

[crash]

is this correct

 

[Denis]

Well, what's the "full problem"?

If it's find sum of 1st 2 terms (n = 2) then:
n(2) = n / (n + 1)
n(2) = 2/3

Now prove it:
1/(2*1) + 1/(3*2) = 1/2 + 1/6 = 3/6 + 1/6 = 4/6 = 2/3

 

[crash]

Well, what's the "full problem"?

If it's find sum of 1st 2 terms (n = 2) then:
n(2) = n / (n + 1)
n(2) = 2/3

Now prove it:
1/(2*1) + 1/(3*2) = 1/2 + 1/6 = 3/6 + 1/6 = 4/6 = 2/3__

n is 1/2*1, so n=1/2

i have to prove this 1/2=1/2 / 1/2+1 ( n= n/n+1), this one is also incorrect xD, ill prove it and continue doing the next problem

i have about 10 minutes till the test starts :?

 

[Denis]

n is a term number, so CANNOT be 1/2; terms are numbered from 1 up: 1,2,3,4,......

So something's wrong with what you're saying...

Anyway, 1/2 / (1/2 + 1) = 1/2 / (3/2) = (1/2) * (2/3) = 1/3

 

[Deleted member 4993]

is this correct

The series above is a telescopic series that can be written as:

1/(1*2) + 1/(2*3) + 1/(3*4) ....1/(n*(n+1))

= (1/1 - 1/2) + (1/2 - 1/3) + (1/3 - 1/4) + (1/4 - 1/5) ......+ (1/n - 1/(n+1))

= 1/1 - 1/(n+1)

and finish it.....