FINAL EXAM

Question 1.
a) A credit union pays interest of 10% per annum compounded monthly on a certain savings plan. If $10000 is deposited in such a plan and the interest is left to accumulate, how much is in the account after 2 years?
b) Solve the following equation: 5x22x1x+1=505^x \cdot 2^{\frac{2x-1}{x+1}} = 50.

Question 2.
Given the following function f(x)=3x+2x1f(x) = \frac{3x+2}{x-1}
a) Find the inverse function of ff.
b) Find the average rate of change of ff from x0x_0 to x0+hx_0 + h, where hh is real.

Question 3.
The area of the opening of a rectangular window is to be 143 square feet. If the length is to be 2 feet more than the width, what are the dimensions?

Question 4.
Solve the following system of linear equations

{x1+2x2+3x3=1x1+3x2+4x3=22x13x25x3=1\begin{cases} x_1 + 2x_2 + 3x_3 = 1 \\ x_1 + 3x_2 + 4x_3 = 2 \\ -2x_1 - 3x_2 - 5x_3 = -1 \end{cases}

Question 5.
Let

A=(1234)A = \begin{pmatrix} 1 & 2 \\ 3 & -4 \end{pmatrix}

and

B=A2+3A10I,B = A^2 + 3A - 10I,

where II is the identity matrix of size 2.

a) Find inverse of AA
b) Find BB
c) Find det(B)\det(B)

Question 6.
Let

B=(11220324m+4)B = \begin{pmatrix} 1 & 1 & 2 \\ -2 & 0 & -3 \\ 2 & 4 & m+4 \end{pmatrix}

where mRm \in \mathbb{R}.

a) Find mm such that BB is invertible
b) Find the inverse of BB when m=0m = 0

Question 7.
One group of people purchased 20 hot dogs and 10 soft drinks at a cost of $85.00. A second bought 8 hot dogs and 3 soft drinks at a cost of $32.50. What is the cost of a single hot dog? A single soft drink?

Question 8.
Maximize z=4x+7yz = 4x + 7y subject to x0x \ge 0, y0y \ge 0, x+y4x + y \ge 4, x+y10x + y \le 10, x+2y6x + 2y \ge 6

Question 9.
a) Given the following polynomial f(x)=x42x3+6x22x+5f(x) = x^4 - 2x^3 + 6x^2 - 2x + 5. Note that f(x)=0f(x) = 0 has a solution x=ix = i. Find all remaining solutions.
b) Show the following number z=(2+2i)6z = (2 + 2i)^6 in the form of a+bia + bi.

Question 10.
Let A,BA, B be two square matrices of size nn such that ABAB=0AB - A - B = 0. Prove that AB=BAAB = BA

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