Question

If s=1+2+3+4+............................…....+100

then find the value of s​

Answer 1

Answer:

s=1+2+3+.................+100

a=1,d=2-1=1 ,n=100 ,s=?

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

=100/2{2(1)+(100-1)1}

=50(2+99)

=50(101)

=5050

Answer 2

Answer:

Step-by-step explanation:

S=1+2+3+4+5+6+……………. +95+96+97+98+99+100.

S=(1+100)+(2+99)+(3+98)+(4+97)+(5+96)+……………..+50 terms.

S=101+101+101+101+101+101+………………….50 term

S =101×50 = 5050. Answer.

Second - method:-

S=1+2+3+4+5+6+…………………….+100.

This is an A.P. in which a=1 , d=1 ,n=100 .

Sn=(n/2).[ 2.a+(n-1).d]

S100 = 100/2.[2.1+(100-1).1]

= 50.[ 2+99]

=50×101 = 5050. Answer.