Question

If nth term is 4-2n find the sum first 3 term

Answer 1

Substitute values In the place of n
tn = 4 - 2n
t1 = 4 - 2(1)
t2 = 4 - 4 = 0
t3 = 4 - 6 = - 2
Sum of three terms is 4

Answer 2

Answer:

0

Step-by-step explanation:

Since nth teen = 4 - 2n,

1st term = 4 - 2(1) = 4 - 2 = 2

2nd term = 4 - 2(2) = 4 - 4 = 0

Therefore, common difference = 2nd term - 1st term = 0 - 2 = -2

Sum of first n terms = n/2 [2a + (n-1) d]

Hence, sum of first there terms = 3/2 [2 × 2 + (3-1) × (-2)] = 1.5 [4 + (2)(-2)] = 1.5 [4 - 4] = 1.5[0] = 0