an=4n+1
Sum of first 30 terms
a1+a2+.................a30
Sn=(a1+an)*n/2
a1-----------first
terms
an=---------last
term-----a30
n= number of
terms-----30
calculation of a1
a1=4n+1=4*1+1=5
calculation of an
a30=4*30+1=121
S30=(a1+a30)*30/2
S30=(5+121)*30/2=1890
The sum of first
30 terms is 1890
