Question

sum of first six
term of an ap is 6 .
Product of second and fifth term is -80, Write the term of AP?​

Answer 1

Step-by-step explanation:

Given:

S10=99+T1..........(i)S10=89+T6..........(ii)

where S10 is the sum of 10 terms of the A.P. and T1,T6 are the first and sixth term respectively.

Say a and d are the first term and common difference of the A.P. respectively.

∴S10=5{2a+9d};T1=a;T6=a+5d........(iii)∴5{2a+9d}=a+99........(iv)5{2a+9d}=a+89+5d........(v)

Subtracting (iv) and (v), we get,

10−5d=0=>d=2........(vi)

Also given that

T1+T5=10=>a+a+4d=10=>2a+4×2=10=>2a=2=>a=1

∴T3=a