Q10 of 114 Page 3

Observe the following pattern


And find the values of each of the following.


(i)


(ii)

R.H.S = [(No. of terms in L.H.S) × (No. + 1) × (2 × No. + 1)]

(i) 12 + 22 + 32 + 42 + …… + 102 = [10 (10 + 1) × (2 × 10 + 1)]


= [2310]


= 385


(ii) 52 + 62 +….. + 122 = 12 + 22 + ….. 122 – (12 + 22 + 33 + 42)


= [12 × (12 + 1) × (2 × 12 + 1)] - [4 ×(4 + 1) × (2 × 4 + 1)]


= 650 – 30


= 620


More from this chapter

All 114 →
8

Observe the following pattern


And find the value of


 9

Observe the following pattern



And find the values of each of the following:


(i) 1+2+3+4+5+……….+50


(ii) 31+32+……..+50

 11

Which of the following numbers are squares of even numbers?

121, 225, 256, 324, 1296, 6561, 5476, 4489, 373758

 12

By just examining the units digits, can you tell which of the following cannot be whole squares?

(i) 1026 (ii) 1028


(iii)1024 (iv) 1022


(v) 1023 (vi) 1027