PRELIM EXAM (AENMAT EN1/EN2)
  • 1. Which is true about complex numbers?
A) All of the choices
B) the symbol j and i denotes same value
C) The imaginary number part of it is the square root of the negative number.
D) It contains both real and imaginary number.
  • 2. Which of the following is an example of complex number
A) 2+3i
B) 15
C) All of the choices are considered
D) rcis30
  • 3. Determine (3 - 5i) + (-4 + 7i)
A) 1 + 2i
B) 7 - 12i
C) 7 +12i
D) -1 +2i
  • 4. A complex number can only be added or subtracted directly if it is in __________
A) exponential form
B) trigonometric form
C) rectangular form
D) polar form
  • 5. 5+3i equivalent to
A) 5.83cis0.54 rad
B) 5.83∠30.96°
C) e0.54i
D) all of the choices
  • 6. i21equivalent to
A) 1
B) -i
C) i
D) -1
  • 7. Determine (3 - 5i) - (-4 + 7i)
A) 1 + 2i
B) -1 +2i
C) 7 - 12i
D) 7 +12i
  • 8. Evaluate (4 - i) / ( 1 + 2i)
A) 37-3i
B) -0.4 + 1.8i
C) 0.4 - 1.8i
D) 37 +3i
  • 9. Compute for the modulus of the complex number -2√3 +3√2i.
A) 0
B) 2√5
C) √30
D) √ 5
  • 10. Compute for the argument of the complex number 1-√3 i
A) π/3
B) -π/6
C) 5π/3
D) 2π/3
  • 11. Find the argument of the complex number -3-4i in radians
A) 0.93
B) 5.35
C) 2.22
D) 0.93
  • 12. i29 + i21+ i
A) 3∠90
B) all of the choices are considered
C) -3i
D) 3e-1.571i
  • 13. (12∠30°)+ (8∠25°) - (6∠-20°)
A) all of the choices are considered
B) 16.58e0.761i
C) 16.58∠43.60°
D) 12.01+11.43i
  • 14. (2+2i)(7∠π/6)
A) 14√2 ∠75°
B) 14√2 ∠-75°
C) 5.12-19.12i
D) -5.12+19.12i
  • 15. (4+3i) / (2-i)
A) 2.24e-5.176i
B) 2.236 ∠-63.43°
C) None of the choices are correc
D) 1-2i
  • 16. Compute the product of z1 = 2(cos 30° + i sin 30° ), z2 = 2√2 (cos π/2 +i sin π/2) and z3 = cos 45° +i sin 45°. Express in rectangular form
A) -5.47 +1.47i
B) (2-2√3)+(-2-2√3 i)
C) +5.47 -1.47i
D) (-2-2√3)+(-2-2√3 i)
  • 17. (4+8i)/ i28
A) none of the choices
B) -8+4i
C) 12-3i
D) 4+8i
  • 18.
A) 20.30∠166.67
B) 4.68+19.75i
C) 20.30∠-76.67
D) 20.30 e-1.34i
  • 19. (3+5i)4/(2+6i)3
A) 4.6 e0.374i
B) 4.6 ∠-338.55°
C) -4.25 + 1.67i
D) none of the choices
  • 20. find the cube root of 8 when k=1
A) 2∠120°
B) all of the choices are correct
C) 2∠240°
D) 2∠0
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