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1. (a)What is the present value of an annuity of monthly payments of e 500 over 25 years earning 2% p.a. interest compounded monthly?

(b)  Find the annual percentage rate (APR) for the following interest rates

(i) 3.39% p.a. compounded annually
(ii) 3.29% p.a. compounded semi-annually,

(iii) 3.35% p.a. compounded quarterly, (iv) 3.4% p.a. compounded monthly .

Which of these gives the cheapest option when taking out a loan for two years? How much interest would it cost to borrow e1,000 for two years under the cheapest option?

(c)  Find the final value of a savings account into which e 1000 are paid every three months for 10 years, if the bank is paying 2.5% p.a. interest compounded quar- terly.

(d)  Differentiate each of the following functions and find the value of the derivative when x = 1:

(i) f(x)=2−3ln(x)+3x, 1 + 2x2ex

(ii)g(x)= 1+x2 ,


(e) Letf(x)=x3 −2x2 −4x.

(i) Find f′(x) and f′′(x).
(ii) Determine the critical points of f.

(iii) Show that x = −2 is a local maximum of f. 3

 Jul 7, 2016

Best Answer 

 #4
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I have them done I'm just looking for solutions to ensure I'm right! Thank you melody for help! 

 Jul 7, 2016
 #1
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1(a) $500 x (1+2%)25 x 12

    = $500 x 1.0230

     = $905.6807920516769 

    \(\approx\) $ 905.68

(b)(i)\(\quad(\frac{1+0.0339}{1})^1-1\\ = 0.0339\)

APR = 3.39%

 

(b)(ii) \(\quad (\frac{2+0.0329}{2})^2-1\\ = 0.033170602.....\)

APR = 3.32.....%

 

(b)(iii) \(\quad (\frac{4+0.0335}{4})^4-1\\ = 0.033923......\)

APR = 3.392.....%

(b)(iv) \(\quad (\frac{12+0.034}{12})^{12}-1\\=0.0345348......\)

APR = 3.45......%

Which of these gives the cheapest option when taking out a loan for two years?

3.29% p.a. compounded semi-annually.

 

How much interest would it cost to borrow $1,000 for two years under the cheapest option?

1000 x 3.32% x 2

= $66.4

(c) 1000 x (1+2.5%)4 x 10

= 1000 x 2.685063838

= $2685.1 approx.

 

(d) f(x) = 2 - 3ln(x) + 3x

\(f'(x)= \frac{3}{x}+3\\ f'(1)= \frac{3}{1}+3 = 6\)

f(x) = 2x2ex

\(f'(x)= 2xe^x(x+2)\\ f'(1)= 2(1)(e)(1+2)= 6e\)

 

g(x) = 1 + x2

\(g'(x)= 2x\\ g'(1)= 2(1)=2\)

 

(e) \(f(x)=x^3-2x^2-4x\\ f'(x)= 3x^2-4x-4\\ f''(x)= 6x-4\)

 

I don't know what's critical point and local maximum.......

 Jul 7, 2016
 #2
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Come on Kcc - We are not here to do all your homework for you!

 Jul 7, 2016
 #4
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Best Answer

I have them done I'm just looking for solutions to ensure I'm right! Thank you melody for help! 

Kcc2468  Jul 7, 2016
 #3
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Max: Everything appears to be right in your calculations except this one:

(c)  Find the final value of a savings account into which e 1000 are paid every three months for 10 years, if the bank is paying 2.5% p.a. interest compounded quar- terly.

 

FV=P{[1 + R]^N - 1/ R}=FV OF $1 PER PERIOD.

FV=1,000[1 + .025/4]^(10*4) -1/(.025/4)}

FV=1,000{[1.283027 - 1] / .00625}

FV=1,000 x 45.284291

FV=45,284.29e

 Jul 7, 2016
 #5
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We are here to help people learn kcc.

It is best that you are up front about what kind of help that you need.

We don't have time to answer everyone's questions so help us to know which of yours have priority.

There is no need for us to redo all your homework unless you have real concerns that you have not really understood.

So tell us what you did and let us comment on your work.

You will get better reactions from us long term if we feel you are using our expertise and time to learn the from us in the best, most efficient manner :))

 

We knock ourselves out for students who show us very clearly that they are learning from us and not using us for anything other than learning purposes.  :)

 Jul 7, 2016
 #6
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I am sure I speak for MaxWong and our answering guests as well as for myself when I say that we are very pleased that we are helping you.

 

Welcome to the Web2.0 forum Kcc2468  laugh

 Jul 7, 2016

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