Question

Find the sum of first n natural numbers and hence find sum of first 100 natural numbers [this is a question from chapter arithmetic progressions]

Answer 1

Answer:

SUM OF FIRST n TERMS OF AN AP= (n^2+n)/2

SUM OF FIRST 100 NATURAL NUMBERS = 5050

Step-by-step explanation:

SUM OF FIRST n TERMS OF AP =

a= 1 d= 1. n= n

Sn = n/2 {2a+(n-1)d}

= n/2 {2(1)+(n-1)1}

= n/2 (2+n-1)

= n/2 (n+1)

= (n^2+n)/2

SUM OF FIRST 100 NATURAL NUMBERS

a=1. d=1. n= 100. an=100

S100= 100/2 (1+100)

= 50 (101)

= 5050

HOPE IT HELPED YOU

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