Tom has i cent for the first day , 2 cents for the second day , 4 cents for the third day , 8 cents for the fourth day... and so on
According to his request , how many dollars will he earn on the 31st day?In scientific notation, correct to 3 signicficant figures.
Thx for helping :P
F.2 maths (scientific notaion)
2011-08-26 6:05 am
回答 (2)
2011-08-26 11:04 am
✔ 最佳答案
The general term of a geometric sequence is given by:tn =ar^(n-1)
where a is the first term, n is the number of term, r is the common ratio
1 + 2 + 4 + 8 ...+ .... t31
a = 1, n = 31, r = 2 (given)
t31 = (1) 2^(31-1)
t31 = 2^30
t31 = 1073741824
On 31st day, he will earn 1073741824 cents
1073741824 cents = $10737418.24 = 10737418 dollars 24 cents
In scientific notation, correct to 3 significant figures.
$10737418.24 = 1.07 x 10^7 dollars
10^7 means 10 raised to the power of 7.
2011-08-26 03:09:13 補充：
Correction:
$10737418.24 = 1.07 x 10^7 dollars
I should not put an equal sign = there!
On 31st day, Tom will earn 1.07 x 10^7 dollars
(In scientific notation, correct to 3 significant figures.)
2011-08-26 7:24 am
By G.S.,
a = 1, R = 2,
Amount he will earn
= 1 + 2 + 4 + 8 + ... + 2^30
= 1(1-2^30)/(1-2)
= (1-1073741824)/(-1)
= $1073741823
a = 1, R = 2,
Amount he will earn
= 1 + 2 + 4 + 8 + ... + 2^30
= 1(1-2^30)/(1-2)
= (1-1073741824)/(-1)
= $1073741823
參考: Hope the solution can help you^^”
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