Question

The nth term of an AP is given by tn=a+bn. show that it is an AP. Find its first term and common difference. ​

Answer 1

Step-by-step explanation:

nth term of a.p

tn= 3n+4

put value of n = 1,2,3

n= 1

t1= 3×1+4= 3+4=7

n= 2

t2=3×2+4=6+4=10

n=3

t3=3×3+4=9+4=13

to find difference t2-t1

10-7=3

t3-t2

13-10=3

so the difference is 3

sum of the first five term

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

s1=1/2[2×7+(1-1)3]

s1=1/2(14+0)

s1=1×7

s1=7