Question

( a_{1}, a_{2}, a_{3} ldots a_{n}=A P quad d rightarrow operatorname{com} m x )
( mathrm{LHS} )
( frac{1}{a_{1} a_{2}}+frac{1}{a_{12} a_{3}} cdot-cdots+frac{1}{a_{i n-1} a_{n}} )

# dejan + as lai) djant van a + (n − 1) d- a an.... , an be an A.P. of non-zero terms, prove that dijant jay n -1 jantan de EXAMPLE 21 If 1 an az + 1 A2 A3 +...+-1 An-1an _n-1 anai

Solution