Trigonometric Expansions and Summations - Question Bank

1. The expansion of cos(A+B+C) uses the identity: cos(X+Y) = cosXcosY - sinXsinY, where X=A and Y=B+C.
A) True
B) False
C) Partially True
D) Depends on the values of A, B, C
2. The expansion of sin(A+B+C) uses the identity: sin(X+Y) = sinXcosY + cosXsinY, where X=A and Y=B+C.
A) True
B) False
C) Partially True
D) Depends on the values of A, B, C
3. What is the general formula for cos(nA) in terms of sinA and cosA, using De Moivre's theorem?
A) Re( (cosA + i sinA)^n )
B) Im( (cosA + i sinA)^n )
C) (cosA + i sinA)^n
D) sin(nA)
4. What is the general formula for sin(nA) in terms of sinA and cosA, using De Moivre's theorem?
A) Im( (cosA + i sinA)^n )
B) Re( (cosA + i sinA)^n )
C) (cosA + i sinA)^n
D) cos(nA)
5. The sum ∑_{k=1}^{n} cos(kx) can be evaluated using:
A) Complex exponentials or product-to-sum identities
B) Direct summation
C) Taylor series
D) Integration
6. The sum ∑_{k=1}^{n} sin(kx) can be evaluated using:
A) Complex exponentials or product-to-sum identities
B) Direct summation
C) Taylor series
D) Integration
7. What is the value of tan(75 degrees) using sum/difference formulas?
A) 2 + sqrt(3)
B) 2 - sqrt(3)
C) 1
D) sqrt(3)
8. What is the value of cos(75 degrees) using sum/difference formulas?
A) (sqrt(6) - sqrt(2)) / 4
B) (sqrt(6) + sqrt(2)) / 4
C) (sqrt(3) - 1) / (2*sqrt(2))
D) (sqrt(3) + 1) / (2*sqrt(2))
9. What is the value of sin(15 degrees) using sum/difference formulas?
A) (sqrt(6) - sqrt(2)) / 4
B) (sqrt(6) + sqrt(2)) / 4
C) (sqrt(3) - 1) / (2*sqrt(2))
D) (sqrt(3) + 1) / (2*sqrt(2))
10. The expression cos^2 A is related to cos(2A) by:
A) (1 + cos(2A)) / 2
B) (1 - cos(2A)) / 2
C) sin^2 A
D) cos(A)
11. The expression sin^2 A is related to cos(2A) by:
A) (1 - cos(2A)) / 2
B) (1 + cos(2A)) / 2
C) cos^2 A
D) sin(A)
12. What is the sum of angles in the denominator of the tan(A+B+C) expansion?
A) AB+BC+CA
B) A+B+C
C) AB
D) BC
13. What is the sum of angles in the numerator of the tan(A+B+C) expansion?
A) A+B+C
B) A+B
C) A+C
D) B+C
14. The expansion of cos(A+B+C) involves how many product terms of sines and cosines?
A) Four
B) Three
C) Two
D) One
15. The expansion of sin(A+B+C) involves how many product terms of sines and cosines?
A) Four
B) Three
C) Two
D) One
16. What is the formula for cos(A-B) - cos(A+B)?
A) 2 sinA sinB
B) 2 sinA cosB
C) 2 cosA sinB
D) 2 cosA cosB
17. What is the formula for cos(A+B) + cos(A-B)?
A) 2 cosA cosB
B) 2 sinA cosB
C) 2 cosA sinB
D) 2 sinA sinB
18. What is the formula for sin(A+B) - sin(A-B)?
A) 2 cosA sinB
B) 2 sinA cosB
C) 2 cosA cosB
D) 2 sinA sinB
19. What is the formula for sin(A+B) + sin(A-B)?
A) 2 sinA cosB
B) 2 cosA sinB
C) 2 cosA cosB
D) 2 sinA sinB
20. What is the expansion of cos(nA) for integer n?
A) A power series in cosA and sinA
B) A polynomial in sinA
C) A polynomial in cosA
D) A constant value
21. What is the expansion of sin(nA) for integer n?
A) A power series in sinA and cosA
B) A polynomial in sinA
C) A polynomial in cosA
D) A constant value
22. If A+B+C = pi, what is the relation between tangents of the angles?
A) tanA + tanB + tanC = tanA tanB tanC
B) tanA + tanB + tanC = -tanA tanB tanC
C) tanA tanB tanC = 1
D) tanA + tanB + tanC = 0
23. If A+B+C = pi, what is the value of tan(A+B+C)?
A) 0
B) Undefined
C) tanA + tanB + tanC
D) 1
24. If A+B+C = pi, what is the value of cos(A+B+C)?
A) -1
B) 1
C) 0
D) cosA cosB cosC
25. What is the expansion of sin(A+B+C) if A+B+C = pi?
A) 0
B) 1
C) sinA + sinB + sinC
D) cosA + cosB + cosC
26. What is the sum-to-product formula for cosC - cosD?
A) -2 sin((C+D)/2) sin((C-D)/2)
B) 2 sin((C+D)/2) cos((C-D)/2)
C) 2 cos((C+D)/2) sin((C-D)/2)
D) 2 cos((C+D)/2) cos((C-D)/2)
27. What is the sum-to-product formula for cosC + cosD?
A) 2 cos((C+D)/2) cos((C-D)/2)
B) 2 sin((C+D)/2) cos((C-D)/2)
C) 2 cos((C+D)/2) sin((C-D)/2)
D) 2 sin((C+D)/2) sin((C-D)/2)
28. Express sinC - sinD using sum-to-product formulas.
A) 2 cos((C+D)/2) sin((C-D)/2)
B) 2 sin((C+D)/2) cos((C-D)/2)
C) 2 cos((C+D)/2) cos((C-D)/2)
D) 2 sin((C+D)/2) sin((C-D)/2)
29. What is the sum-to-product formula for sinC + sinD?
A) 2 sin((C+D)/2) cos((C-D)/2)
B) 2 cos((C+D)/2) sin((C-D)/2)
C) 2 cos((C+D)/2) cos((C-D)/2)
D) 2 sin((C+D)/2) sin((C-D)/2)
30. What is the product-to-sum formula for 2 sinA sinB?
A) cos(A-B) - cos(A+B)
B) cos(A+B) + cos(A-B)
C) sin(A+B) + sin(A-B)
D) sin(A+B) - sin(A-B)
31. What is the formula for 2 cosA cosB?
A) cos(A+B) + cos(A-B)
B) cos(A-B) - cos(A+B)
C) sin(A+B) + sin(A-B)
D) sin(A+B) - sin(A-B)
32. Express 2 cosA sinB as a sum or difference.
A) sin(A+B) - sin(A-B)
B) sin(A+B) + sin(A-B)
C) cos(A+B) + cos(A-B)
D) cos(A-B) - cos(A+B)
33. What is the product-to-sum formula for 2 sinA cosB?
A) sin(A+B) + sin(A-B)
B) sin(A+B) - sin(A-B)
C) cos(A+B) + cos(A-B)
D) cos(A-B) - cos(A+B)
34. What is the expansion of tan(A+B+C)?
A) (tanA + tanB + tanC - tanA tanB tanC) / (1 - tanA tanB - tanB tanC - tanC tanA)
B) (tanA + tanB + tanC + tanA tanB tanC) / (1 - tanA tanB - tanB tanC - tanC tanA)
C) tanA + tanB + tanC
D) (tanA + tanB + tanC) / (1 - tanA tanB tanC)
35. Expand cos(A+B+C).
A) cosA cosB cosC - cosA sinB sinC - sinA cosB sinC - sinA sinB cosC
B) sinA cosB cosC + cosA sinB cosC + cosA cosB sinC - sinA sinB sinC
C) cosA cosB cosC + cosA sinB sinC + sinA cosB sinC + sinA sinB cosC
D) cosA + cosB + cosC
36. What is the formula for sin(A+B+C)?
A) sinA cosB cosC + cosA sinB cosC + cosA cosB sinC - sinA sinB sinC
B) sinA cosB cosC + cosA sinB cosC + cosA cosB sinC + sinA sinB sinC
C) cosA cosB cosC - cosA sinB sinC - sinA cosB sinC - sinA sinB cosC
D) sinA + sinB + sinC
37. What is the expansion of tan(3A)?
A) (3 tanA - tan^3 A) / (1 - 3 tan^2 A)
B) 3 tanA - tan^3 A
C) (tanA + tan(2A)) / (1 - tanA tan(2A))
D) sin(3A) / cos(3A)
38. Expand cos(3A).
A) 4 cos^3 A - 3 cosA
B) 3 sinA - 4 sin^3 A
C) 3 tanA - tan^3 A / (1 - 3 tan^2 A)
D) cosA cos(2A) - sinA sin(2A)
39. What is the expansion of sin(3A)?
A) 3 sinA - 4 sin^3 A
B) 4 cos^3 A - 3 cosA
C) 3 tanA - tan^3 A / (1 - 3 tan^2 A)
D) sinA cos(2A) + cosA sin(2A)
40. Expand tan(2A).
A) 2 tanA / (1 - tan^2 A)
B) sin(2A) / cos(2A)
C) 2 sinA cosA / (cos^2 A - sin^2 A)
D) (tanA + tanA) / (1 - tanA tanA)
41. What is cos(2A) in terms of sinA only?
A) 1 - 2 sin^2 A
B) cos^2 A - sin^2 A
C) 2 cos^2 A - 1
D) 2 sinA cosA
42. Express cos(2A) in terms of cosA only.
A) 2 cos^2 A - 1
B) cos^2 A - sin^2 A
C) 1 - 2 sin^2 A
D) 2 sinA cosA
43. Expand cos(2A) using both sinA and cosA.
A) cos^2 A - sin^2 A
B) 2 sinA cosA
C) 2 cos^2 A - 1
D) 1 - 2 sin^2 A
44. What is the value of sin(2A) in terms of sinA and cosA?
A) 2 sinA cosA
B) cos^2 A - sin^2 A
C) 2 cos^2 A - 1
D) 1 - 2 sin^2 A
45. Expand tan(A-B).
A) (tanA - tanB) / (1 + tanA tanB)
B) (tanA + tanB) / (1 - tanA tanB)
C) (tanA - tanB) / (1 - tanA tanB)
D) (tanA + tanB) / (1 + tanA tanB)
46. What is the expansion of cos(A-B)?
A) cosA cosB + sinA sinB
B) cosA cosB - sinA sinB
C) sinA cosB - cosA sinB
D) sinA cosB + cosA sinB
47. Expand sin(A-B).
A) sinA cosB - cosA sinB
B) sinA cosB + cosA sinB
C) cosA cosB - sinA sinB
D) cosA cosB + sinA sinB
48. What is the expansion of tan(A+B)?
A) (tanA + tanB) / (1 - tanA tanB)
B) (tanA - tanB) / (1 + tanA tanB)
C) (tanA + tanB) / (1 + tanA tanB)
D) (tanA - tanB) / (1 - tanA tanB)
49. Expand cos(A+B).
A) cosA cosB + sinA sinB
B) cosA cosB - sinA sinB
C) sinA cosB + cosA sinB
D) sinA cosB - cosA sinB
50. What is the value of sin(A+B) expanded?
A) sinA cosB + cosA sinB
B) sinA cosB - cosA sinB
C) cosA cosB + sinA sinB
D) cosA cosB - sinA sinB