Alternating Partial Harmonic Series (1 Viewer)

asharnadeem

New Member
Joined
Aug 8, 2020
Messages
15
Gender
Male
HSC
2021
Prove that 1-1/2+1/3-1/5+.....(-1)^n-1(1/n)>0 for all positive n integers by mathematical induction.
 

Qeru

Well-Known Member
Joined
Dec 30, 2020
Messages
368
Gender
Male
HSC
2021
Prove that 1-1/2+1/3-1/5+.....(-1)^n-1(1/n)>0 for all positive n integers by mathematical induction.
There really isn't a need for induction here. All you have to note is that and and so on until add all of these inequalities and you get your desired result.
 

Etho_x

Joined
Jun 21, 2019
Messages
825
Location
Sydney
Gender
Male
HSC
N/A
There really isn't a need for induction here. All you have to note is that and and so on until add all of these inequalities and you get your desired result.
Just wanted to drop by and say that it’s 1:49am and it’s illegal for your brain to think like this at this time of night

My job is done and I bid you farewell
 

idkkdi

Well-Known Member
Joined
Aug 2, 2019
Messages
2,478
Gender
Male
HSC
2021
Prove that 1-1/2+1/3-1/5+.....(-1)^n-1(1/n)>0 for all positive n integers by mathematical induction.
group into pairs first two in one pair 3 and 4 in second pair. 1st number bigger than 2nd number every time.
for induction proof we assume two cases.
(-1)^n 1/n+1 where n is odd. positive pairs + positive number. trivial
where n is even.
sum of positive pairs. trivial.
 
Last edited:

Qeru

Well-Known Member
Joined
Dec 30, 2020
Messages
368
Gender
Male
HSC
2021
Just wanted to drop by and say that it’s 1:49am and it’s illegal for your brain to think like this at this time of night

My job is done and I bid you farewell
I'm a night person :)
 

Etho_x

Joined
Jun 21, 2019
Messages
825
Location
Sydney
Gender
Male
HSC
N/A
he forgot the case where its an odd number of numbers and not all can be grouped into pairs :).
Tbh I haven’t even started on mathematical induction yet so I’m just randomly saying shit LMAO
 

Qeru

Well-Known Member
Joined
Dec 30, 2020
Messages
368
Gender
Male
HSC
2021
he forgot the case where its an odd number of numbers and not all can be grouped into pairs :).
I assumed it was obvious guess I should have explained more.
 

Drdusk

Moderator
Moderator
Joined
Feb 24, 2017
Messages
2,021
Location
a VM
Gender
Male
HSC
2018
Uni Grad
2023
group into pairs first two in one pair 3 and 4 in second pair. 1st number bigger than 2nd number every time.
Grandi’s series would like to: Know your location.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top