Question

Evaluate the summation of 3 times negative 2 to the n minus 1 power, from n equals 1 to 5. . (2 points)


−93
−33
33
93

Answer 1

To answer the question, we may directly use the calculator by inputting the expression 3 x (-2)^(n - 1) or manually as follows,

n = 1 ;     3 x (-2)^(1 - 1) = 3
n = 2 ;     3 x (-2)^(2 - 1) = -6
n = 3 ;     3 x (-2)^(3 - 1) = 12
n = 4 ;     3 x (-2)^(4 - 1) = -24
n = 5 ;     3 x (-2)^(5 - 1) = 48

                               S = 3 - 6 + 12 - 24 + 48 = 33

Thus, the summation is equal to 33 which is the third among the four choices.