Question

Do the numbers 5,55,555 form of a G.P? justify

Answer 1

Answer:

Step-by-step explanation:

Here's the series:

5+55+555+5555+......

What is the general formula to find the sum of n-th terms?

My attempts:

I think I need to separate 5 from this series such that:

5(1+11+111+1111+....)

Then, I think I need to make the statement in the parentheses into a easier sum:

5(1+(10+1)+(100+10+1)+(1000+100+10+1)+.....)

= 5(1∗n+10∗(n−1)+100∗(n−2)+1000∗(n−3)+....)

Until the last statement, I don't know how to go further. Is there any ideas to find the general solution from this series?

Thanks

Answer 2

Answer:

Step-by-step explanation:

Here's the series:

5+55+555+5555+......

What is the general formula to find the sum of n-th terms?

My attempts:

I think I need to separate 5 from this series such that:

5(1+11+111+1111+....)

Then, I think I need to make the statement in the parentheses into a easier sum:

5(1+(10+1)+(100+10+1)+(1000+100+10+1)+.....)

= 5(1∗n+10∗(n−1)+100∗(n−2)+1000∗(n−3)+....)

Until the last statement, I don't know how to go further. Is there any ideas to find the general solution from this series?

Thanks