sequence series

[narrow gulch]

How to do these type of problems they're pretty prevalent in the pyqs

[carmine fog]

<@&1227988399579730072>

Note for OP

+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.

[crisp pier]

Notice that the 1st terms of the first row is 1 and for the second row it is 1+1=2. For the third row it is (1+2)+1=4 and for the fourth row it is (1+2+3)+1=7

This is due to the fact that the k th row has k terms.

So the number of terms before the k th row is sum of n from 1 to k-1

Hence the first term of the k th wor is k(k-1)/2+1

Now try to see where 5310 will lie.

[narrow gulch]

yes yes

[narrow gulch]

i see
and last term ka kya?

[crisp pier]

Agle row ke pehle term se ek peeche

Toh must be k(k+1)/2

[narrow gulch]

yeah oki

imma try this

so 5310 lies between k(k-1)/2 and k(k+1)/2

yeah got it

thanks alot

[crisp pier]

Np.

[narrow gulch]

+solved @crisp pier