Posted by Anonymous on .
How many terms are required in the series (6) + (12) + (24)... to add to a sum of 378?
How do I do this?

Calculus 
Reiny,
looks like a geometric series where
a = 6 and r = 2
Term(n) = a(r^n  1)/(r1), where n is the number of terms
378 = 6(2^n  1)/(21)
63 = 2^n  1
64 = 2^n
I know that 2^6 = 64
so n=6
so you need 6 terms. 
Calculus 
Anonymous,
Thank you so much, could you please help me with my other calculus posts.