Answer:
see explanation
Step-by-step explanation:
The n th term ( explicit formula ) of an arithmetic sequence is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₁₂ = - 95 and a₃₇ = - 270 , then
a₁ + 11d = - 95 → (1)
a₁ + 36d = - 270 → (2)
Subtract (1) from (2) term by term to eliminate a₁
25d = - 175 ( divide both sides by 25 )
d = - 7
Substitute d = - 7 into (1) and solve for a₁
a₁ + 11(- 7) = - 95
a₁ - 77 = - 95 ( add 77 to both sides )
a₁ = - 18 , thus
= - 18 - 7(n - 1) = - 18 - 7n + 7 = - 7n - 11
= - 7n - 11 ← explicit formula
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The recursive formula allows a term in the sequence to be found by adding the common difference d to the previous term, thus
= - 7 with a₁ = - 18 ← recursive formula
To start, you know that this question is asking for the surface area of one of the cylinders, and the formula to finding the surface area of a cylinder is A=2πrh+2<span>πr^2.
Now, to find the surface area, you first need to figure out the height of the plastic cylinder and its radius.
Since you know that the diameter (twice the radius) of the cylinder is equivalent to 4 marbles, and each marble has a diameter of 2 cm, the diameter of the cylinder would be 8 cm. Then, to find its radius, you divide by 2, so its radius is 4.
Now, since you know that the height of the cylinder is 10 marbles, you multiply 10 by 2 to get that the height is 20 cm tall.
Since you now have the values of the height and the radius, plug the values into the surface area of a cylinder formula (r is radius and h is height).
</span>A=2π(4)(20)+2π(4)^2.
<span>Assuming that pi is 3.14, when you simplify this using PEMDAS, you get
502.4+100.48 which then simplifies to 602.88, the area of the plastic to make one cylinder.
</span>
<span>If you are given a mean and asked for one of the data values, you can still use the basic method for determining the mean, but work backwards. Generally we add up all the values and then divide by the number of values. In this case, working backwards, we multiply by the number of values (instead of dividing) and then subtract (instead of adding). You should be left with a data value from the set. </span>
880, theres no change in between, only after every 13 years