Question

the rule for the number of line segments, L, between n noncollinear points, in terms of the number of line segments between n-1 points is Ln = Ln-1 + (n-1). how many line segments can be drawn between 12 noncollinear points

Answer 1

@sourav_aich

Answer 2

11 ?

Answer 3

if not how do i do this lol

Answer 4

the minimum no. of noncollinear points is 3
so L3 = L2 + (3-1)
L3 = 1 + 2
L3 = 3.

similarly,

L4 = L3 + (4 - 1)
L4 = 3 + 3
L4 = 6

keep on repeating the above procedure to find the no. of line segments between 12 points.

Answer 5

okay let me try it

Answer 6

okay im confused lol

Answer 7

wait i think i understand now one sec

Answer 8

L12=22 ?

Answer 9

L5 = L4 + (5-1)
L5 = 6 +4
L5 = 10

L6 = L5 + (6-1)
L6 = 10 + 5
L6 = 15

L7 = L6 + (7 - 1)
L7 = 15 + 6
L7 = 21

keep on repeating this till L12 ..

Answer 10

okay i dont undetstand where you're getting the 6, 10, and 15.. those numbers.

Answer 11

L4 = 6

Answer 12

L5 = 10 and L6 = 15

Answer 13

follow the first step
where L2 = 1
because between two points we can have only 1 line segment

Answer 14

okay im completely lost that makes no sense.

Answer 15

where you are stuck

Answer 16

the part i mentioned above. how L4=6 and L5= 10 and L6=15.. i dont understand how you got those numbers.

Answer 17

from the given equation Ln = Ln-1 + (n-1)
put n = 3 then
L3 = L2 + (3 -1)
L3 = 1 + 2
L3 = 3

now put n = 4 then
L4 = L3 + (4 -1)
L4 = 3 + 3
L4 = 6

Answer 18

okay so for 12 it would be L12=L11+(12-1)

Answer 19

yes

Answer 20

and you can get the value of L11 from previous iterations

Answer 21

34 *

Answer 22

is it 34 ?

Answer 23

no

Answer 24

i really thought i had it that time.

L12 = L11 + (12-1)
L12 = 23 + 11

Answer 25

L7 = 21
L8 = L7 + (8 - 1)
L8 = 21 + 7
L8 = 28

L9 = L8 + (9-1)
L9 = 28 + 8
L9 = 36

L10 = L9 + (10 - 1)
L10 = 36 + 9
L10 = 45

L11 = L10 + (11 - 1)
L11 = 45 + 10
L11 = 55

finally
L12 = L11 + (11 - 1)
L12 = 55 + 11
so L12 = 66

Answer 26

okay i think i see what you did.

Answer 27

yes