Question

Jution (1)
+ 50
n(n +1)
Using, 1+2+3+...+n
2
50 x (50 +1)
1+2+3+...+50
1275
2
16 +17 + 18+ ... + 75
= (1+2+3+ ... +75) - (1+2+3+...+15)
75(75 +1) 15(15 +1)
2
2
= 2850 - 120 = 2730
1) Progress Check
of the first n natural
The sum of cubes of first n natural numbers is
numbers.
The average of first 100 natural numbers is
mple 2.55 Find the sum of (i) 1+3+5+ ... + to 40 terms
(ii) 2 +4 +6+ ... + 80 (iii) 1+ 3 + 5 + ... +55
tion (i) 1. +5+. 40 terms = 402 = 1600​

Answer 1

Answer:

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