Question

Find the missing term of the arithmetic sequence: 1,___, 1/5 ?

Answer 1

`a_2=3/5`

Explanation:

arithmetic sequence:
`a_n=a_1+d`

given:

`a_1=1`
`a_2=?`
`a_3=1/5`

so:
`a_3=a_1+2d => 1/5=1+2d => 2d=-4/5 => d=-4/10=-2/5`
`=>`
`a_2=a_1+d=>a_2=1+(-2/5)=3/5`