Math, asked by Thestudent, 1 year ago

deriavation of n(n+1)(2n+1)/6 i.e the sum of squares of first ‘n' natural numbers

Answers

Answered by QGP
8
Hello Friend,

Here's the proof.

To find the sum of squares, we use the formula of (n+1)³ as shown in the picture.

In the proof, I have used one result directly:

1 + 2 + 3 + ... + n = n(n+1)/2

Proof:
Given series is an A.P. with
First term = 1
Last term = n
Number of terms = n

Sum = n/2 [First term + Last Term]
So, Sum = n/2 [1 + n]
So, Sum = n(n+1)/2

That is, 1 + 2 + 3 + ... + n = n(n+1)/2

I have used this result directly in the proof of sum of squares.


Hope it helps.

Purva
@Purvaparmar1405
Brainly.in
Attachments:

QGP: I added a new image. I have written more clearly there
Thestudent: u gave only one page photo right??so i want the simplification of the where it is written (n+1)^3 -1^3=3S +3n(n+1)/2+n
Thestudent: we need S to get the answer so...can u show the simplifications after the step
QGP: At that place, take LCM in denominator. Here, LCM is 2. So all terms on RHS are multiplied by 2
Thestudent: and what about (n+1)^3 -1^3...??
QGP: There I used the identity:
QGP: (n+1)³ = n³ + 3n² + 3n + 1
QGP: This 1 gets cancelled with (-1) already present
Thestudent: i could not understand properly but anyways thanks for u help support
Thestudent: help n support*
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