Help please on part b

-0.63

Step-by-step explanation: hope it helps

-0.045

Step-by-step explanation:

you first take the derivate of A(t)

A'(t)=1.4e^-0.05t X (-0.05)

A'(t)=-0.07e^-0.05t

so when t=0

amount remaining is -0.07e^-0.05(0) e^0 = 1

so its -0.07

when t=9

do the same thing,

-0.07e^-0.05(9) ---use calculator

-0.045

Step-by-step explanation:

Hello,

First of all, a few remarks:

>>> 1 year is 12 months, right?

>>> Monthly compounding means that each month we compute the interest and they will be included in the investment for the next month.

>>> 6% is an interest per year, it means that to compute the interest for 1 month we need to compute by 6% multiplied by

Let's do it !

At the beginning, we have:

   $8,000

After 1 month, we will have:

After 2 months, we will have:

After n months, we will have

We are looking for n such that

So, we need 108 months to reach this amount, which means 108/12=9 years.

Hope this helps.

Do not hesitate if you need further explanation.

Thank you