Question

The sum of first m terms of an ap is 4 m square minus cm if its 10th term is 107 find the value of n also find

Answer 1

Answer:

Sn = 4m²-m

a1 = S1 = 4(1)²-(1) = 3

a2 = S2-S1 = 4(2)²-2-3 = 16-5 = 11

d = a2-a1 = 11-3 = 8

nth term is 107 (given)

Tn = 107

a1+(n-1)d = 107

3+(n-1)8 = 107

n-1 = 104/8 = 13

=> n = 14

Now,

20th term

T20 = a1+19d

= 3+19×8 = 3 + 152 = 155

Hope de rah thaaaa

Answer 2

Answer:

hey mate the value of n= 155