AMU Engineering 2018 solved paper Solved Paper

Given, a,b,αr are the first term, common difference and r th term of an AP, respectively.
∴αm=a+(m−1)d=

1

n

........(i)
and αn=a+(n−1)d=

1

m

.........(ii)
On subtracting Eq. (ii) from Eq. (i), we get
d(m−1−n+1)=

1

n

−

1

m

⇒d(m−n)=

m−n

mn

⇒d=

1

mn

On putting the value of d in Eq.(i), we get
a=

1

mn

∴a−d=0