Question

The first four terms of an AP whose first term is -2 and the common difference is -2 are
(a) -2,0, 2,4
(b)-2,-4, -8, -16
(c) -2,-4,-6,-8
(d) -2,-4,-8,-16​

Answer 1

Answer:

Option (c) : -2,-4,-6,-8

Step-by-step explanation:

a = -2

d = -2

formula of general term of AP : a(n) = a + (n-1)d

a(1) = -2

a(2) = -2 + (2-1)(-2) = -2-2 = -4

a(3) = -2 + (3-1)(-2) = -2 + 2(-2) = -2-4 = -6

a(4) = -2 + (4-1)(-2) = -2 +3(-2) = -2-6 = -8

ALTERNATE METHOD :

d = a(n+1) - a(n)  >>> a(n+1) = a(n) + d

since we are given with the first term and the general difference, terms can be found by putting n = 1,2,3 as well