2.  An A.P is a sequence of number in which
each term is obtained by adding a fixed
number to the preceding term except
the 1st term.
 This fixed no is called the common
difference{d},this number can be
positive,negative or zero.

3.  =d,where d=1
a a+d a+2d a+3d………………

4. an=a+(n-1)d
 where a is the 1st term
 d is the common difference
 an ,is a number which comes at the nth
term.

5.  Let a=2, d=2, n=12,find an?
 an=a+(n-1)d
 =2+(12-1)2
 =2+(11)2
 =2+22
 Therefore, an=24
hence solved

6. c

7.  S is the sum of 1st n terms.
 So, Sn=n/2{2a+(n-1)d}
 Sn=n/2{a+an}
 Sn=n/2{a+l},where l is the last
term.

8.  Let a=5, d=3, n=10, find Sn?
 We know that,
 Sn=n/2{2a+(n-1)d}
 =10/2{2(5)+(10-1)3}
 =5{10+9(3)}
 =5{10+27}
 =5{37}
 =185
 Sn=185

10. CREDIT
TO
K.K SIR