Question

show that the series
5+6+7+........+105 has 101 terms.

Answer 1

@Hollywood_chrissy this is an arithmetic sequence with first term =5. last term or nth term =105
and common difference= (6-5)=1
so Can you do it now?

Answer 2

so you subtract 5 from all the terms?

Answer 3

no, we don't need to do that

Answer 4

@Hollywood_chrissy have you studied arithmetic sequences?

Answer 5

how many terms are there from 1 to 105 ?

Answer 6

104

Answer 7

@Hollywood_chrissy how many terms are these?
1, 2, 3, 4???

Answer 8

4

Answer 9

well.. 1 to 105 are 105 terms,,as 1 to 3 are 3 terms ,,and not 2..are you getting me/

Answer 10

that;s
(4-1 ) =>3 +1

Answer 11

I meant, just subtract the first term from the last term and add 1.
This will only work, when the terms have a difference of 1 like here.
@Hollywood_chrissy can you tell the no. of terms?

Answer 12

a=5, d=1 and n=101
now use formula
sn=n/2{2a+(n-1)d

Answer 13

now put values in formula.