Question

the first term of an A. Pis 5 and it's 100th term Is -292 find the 50th term also find the sum of the 100 terms. ​

Answer 1

Answer:

Step-by-step explanation:

a = 5

$a_{100}$  = -292

$a_{50}$   = ?

$s_{100}$  = ?

a + 99d = -292

5 + 99d = -292

99d = -292 -5

99d = -297

d = -3

a + 49d = $a_{50}$

5 + 49(-3) = 5 + (- 147) = -142 = $a_{50}$

$s_{100}$ = n/2 [2a + (n-1) d]

= 100/2 [2(5) + (100-1)(-3)]

= 50 [10 + 99(-3)]

= 50 [10 + (-297)]

= 50 [10-297]

= 50 x  (-287)

= - 14,350 = $s_{100}$