A bar model can be used to a subtraction problem by showing how much of it your actually losing or winning so subtract the totals and you have gotten your answer.
Formula for C - 14 dating:
Age = [ ln ( percent/100 ) / ln (1/2 ) ] * 5,730 =
= [ ln ( 0.00921 ) / ln ( 0.5 ) ] * 5.730 =
= [( - 4.68746 ) : ( - 0.6931478 )] * 5,730 =
= 6.7626 * 5,730 = 38,749.56 ≈ 39,000 ( rounded to the nearest thousand )
Answer: The person died about 39,000 years ago.
It is asking you to find the sum of k^2 - 1 from k=1 to k=4. Since that is only 4 numbers, calculating the sum by hand wouldn’t be that bad.
(1^2 - 1) + (2^2 - 1) + (3^2 - 1) + (4^2 - 1) = 26
The easier way to find the sum is to use a few simple formulas.
When we have a term that is just a constant c, the formula is c*n.
When we have a variable k, the formula is k*n*(n+1)/2.
When we have a squared variable, the formula is k*n*(n+1)*(2n+1)/6.
In this case, we have a squared variable k^2 and a constant of -1.
So plug in n=4 to the formulas:
4*5*9/6 - 1*4 = 26
The answer is 26
Hello!
1 cubic centimeter = 0.001 liter
105 cubic centimeters = 0.001 × 105
0.001 × 105 = 0.105
Answer ⇒ 0.105 L
Hope this helps! :)
