Please help Math it's a test
2 answers:
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Answer:
a) The estimates for the solutions of are
and
.
b) The estimates for the solutions of are
and
Step-by-step explanation:
From image we get a graphical representation of the second-order polynomial , where
is related to the horizontal axis of the Cartesian plane, whereas
is related to the vertical axis of this plane. Now we proceed to estimate the solutions for each case:
a)
There are two approximate solutions according to the graph, which are marked by red circles in the image attached below:
,
b)
There are two approximate solutions according to the graph, which are marked by red circles in the image attached below:
,
Answer:
According to the rule of 72, the doubling time for this interest rate is 8 years.
The exact doubling time of this amount is 8.04 years.
Step-by-step explanation:
Sometimes, the compound interest formula is quite complex to be solved, so the result can be estimated by the rule of 72.
By the rule of 72, we have that the doubling time D is given by:
The interest rate is in %.
In our exercise, the interest rate is 9%. So, by the rule of 72:
.
According to the rule of 72, the doubling time for this interest rate is 8 years.
Exact answer:
The exact answer is going to be found using the compound interest formula.
In which A is the amount of money, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per unit t and t is the time the money is invested or borrowed for.
So, for this exercise, we have:
We want to find the doubling time, that is, the time in which the amount is double the initial amount, double the principal.
is double the initial amount, double the principal.
The interest is compounded anually, so
Now, we apply the following log propriety:
So:
The exact doubling time of this amount is 8.04 years.