The answer is 9
sqrt(49) = 7
4^2 = 16
16-7 = 9
Answer:
8 days
Step-by-step explanation:
On day 8, Isabella will save 256 nickels, bringing her total to 510.
_____
The number of nickels saved on day n is 2^n. The total is 2^(n+1)-2.
_____
The above can be written down from your knowledge of binary sequences. If you want a more formal development, read on.
__
The number of nickels saved on day n is a geometric sequence with first term 2 and common ratio 2. The n-th term of the sequence is ...
an = a1·r^(n-1) = 2·2^(n-1) = 2^n
The sum of n terms of the sequence is ...
S = a1(r^n -1)/(r -1) = 2(2^n -1)/(2-1)
S = 2^(n+1) -2
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We want S > 500, so ...
500 < 2^(n+1) -2
502 < 2^(n+1)
251 < 2^n
log(251) < n·log(2)
n > log(251)/log(2)
n > 7.97 . . . . . . . . 8 days or more to save more than 500 nickels
Answer:
( cos40° + isin40°)
Step-by-step explanation:
To divide
= 
[ cos(x₁ - x₂) + isin(x₁ - x₂)
Given
= 
( cos(90 - 50)° + isin(90 - 50)°
= ( cos40° + isin40° )
Answer:
Hi. I am a math teacher. Your correct answer is 210. You're welcome!
