Question

Evaluate the summation of 2 times negative 2 to the n minus 1 power, from n equals 1 to 7..

−256

−84

84

86

Answer 1

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The best and most correct answer among the choices provided by the question is 86.       
    
Hope my answer would be a great help for you.

Answer 2

Answer:

(D) 86

Step-by-step explanation:

According to the question, the equation will be= \sum_{n=1}^{7}2(-2)^{n-1}.

Now,substituting the values of n from 1 to 7 in the above equation, we have

\sum_{n=1}^{7}2(-2)^{n-1} = $2(-2)^{0} + 2(-2)^{1}+ 2(-2)^{2}+ 2(-2)^{3} + 2(-2)^{4}+ 2(-2)^{5}+ 2(-2)^{6}$

=$2-4+8-16+32-64+128$

=$170-84$

=$86$

Hence, the correct answer will be equal to 86.