Question

find the sum of AP series 1+3+6+10+15+....... to n terms​

Answer 1

Step-by-step explanation:

given given AP series is equal to

1 + 3 + 6 + 10 + 15 + ..............upto n

here, a= 1

d= 3-1=2

=6-3=3

= 10-6=4

all values of d are different .therefore ,given a series is not a AP series.

Answer 2

Answer:

next term is 21

Step-by-step explanation:

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