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anonymous
 one year ago
help please!
Evaluate the summation of 20 times 0.5 to the n minus 1 power, from n equals 3 to 12..
9.99
19.95
29.98
39.96
anonymous
 one year ago
help please! Evaluate the summation of 20 times 0.5 to the n minus 1 power, from n equals 3 to 12.. 9.99 19.95 29.98 39.96

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0\[\sum_{n=3}^{12} 20 \times 0.5^{n1}\] This is it, right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I can't help you right now, sorry, g2g for a sec someone else can help. I know the answer for forget the shortcut

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0can someone please help me

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.1\[\large 20 \cdot \left(0.5^{n1}\right)\] start with plugging in \(n=3\) and work your way up to \(n=12\) by adding all the values.

Jhannybean
 one year ago
Best ResponseYou've already chosen the best response.1\[\large 20\cdot (0.5^{31} + 0.5^{41}+0.5^{51}+...+0.5^{121})\]

welshfella
 one year ago
Best ResponseYou've already chosen the best response.0or you can use the formula for the sum of a geometric series Sn = a . (1  r^n)  1  r

welshfella
 one year ago
Best ResponseYou've already chosen the best response.0here a = 20*0.5^2 , n = 11 and r = 0.5

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so would i get 9.99 as the answer
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