MAT1375 Precalculus Fall 2019

Fall 2018 | Professor Kate Poirier

Page 3 of 18

final exam review questions

Final Review

1) Simplify cos and sin to get real numbers

a) cos(11*pi/12)   b) sin(5*pi/12)

2)The vectors v⃗ and v⃗ below are being added. Find the approximate magnitude and directional angle of sum ⃗v = v⃗ + v⃗.

a)  ||v⃗||=6, and θ =60◦, and ||v⃗||=2, andθ =180◦

b)  ||v⃗||=3.7, and θ =92◦, and ||v⃗||=2.2, and θ =253◦

3)   Solve for x without using a calculator.

a) ln(2x + 4) = ln(5x − 5)          b) ln(x+6)=ln(x−2)+ln(3)

4) State the domain of the function f and sketch its graph.

a) f(x) = log(x)   b)f(x)=log(x+7)   c)f(x)=ln(x+5)−1

5) Find the domain, the vertical asymptotes and removable discontinuities of the functions

b)f(x)= x2+2 x2 −6x+8  c) f(x) = 3x+6/x^3 −4x

6)add and subtract the complex numbers

a) (5-2i)+(-2+6i)  b) (-9-i)-(5-3i)

7)Divide by long division.

a) x^3−4x^2+2x+1/ x−2.  b) x^3+6x^2+7x−2/x+3

8) Find all real roots

a)f(x) = 6x^4 + 25x^3 + 8x^2 − 7x − 2.  b) f(x) = 4x^3 + 9x^2 + 26x + 6.

9)Find at least 5 distinct solutions of the equation

a) tan(x) = −1.        b) cos(x) = √2/2       c) sin(x) = −√3/2

10) Find the magnitude and directional angle of the vector.

a) ⟨6, 8⟩.  b) ⟨−2, 5⟩.    c) ⟨−4, −4⟩

 

Test #3/ Solutions

6. (5 points) Determine the exact value of sin (pi/12)

1)First break sin(pi/12) into the subtraction of two degrees

sin(pi/12)=sin(pi/3-pi/4)

2)Then we use the angle summation formula

sin(pi/3-pi/4)=sin(pi/3)*cos(pi/3)-cos(pi/3)*sin(pi/4)

3)After find the sin and cos of each angle given

sqrt(3)/2*sqrt(2)/2-1/2*sqrt(2)/2

4) Then simplify the equation

sqrt(6)/2-sqrt(2)/2

5) simplify the equation by combining

sqrt(6)-sqrt(2)/2

Webwork – remaining sets

We’ll finish up course material on Thursday, but you can get started on remaining Webwork sets now.

  • Complex Numbers – Direction
    • you can complete all problems now
    • “argument” means “angle” or “direction”
  • Complex Numbers – Magnitude
    • you can complete all problems now
  • Complex Numbers – Polar Form
    • you can complete most problems now
    • you can find the modulus (magnitude) and angle or $a+bi$ form of complex numbers $\zeta$ now
    • ignore questions asking you for the product $\zeta_1 \cdot \zeta_2$ or quotient $\zeta_1 \div \zeta_2$ until after Thursday’s class
  • Vectors – Components
    • you can complete all problems now
  • Vectors – Magnitude and Direction
    • you can complete all problems now
  • Vectors – Unit Vectors
    • ignore this set until after Thursday’s class

 

Webwork – all sets reopened

All Webwork  sets have been reopened. You have until Wednesday, December 18 to complete anything you didn’t complete previously. Please note that while most sets are due at 11:59pm, the following sets are due at 11:58pm (these are the sets corresponding to topics we’re discussing now):

  • Complex Numbers – Direction
  • Complex Numbers – Magnitude
  • Complex Numbers – Operations
  • Complex Numbers – Polar Form
  • Sequences – Binomial Theorem
  • Vectors – Components
  • Vectors – Magnitude and Direction
  • Vectors – Unit Vectors
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