# ECAT – Mathematics (Numbers Systems)

The following questions are from the basics of numbers systems, rational and irrational numbers, complex numbers and their properties.

## Mathematics-Number Systems Sample Questions

1. If a = b and b = c, then a = c. This property is called ?
(A) Reflexive
(B) Transitive
(C) Trichotomy
(D) Symmetric

2. If a > b and b > a, then ?
(A) a = b
(B) a ≠ b
(C) cannot be evaluated
(D) impossible

3. π (pi) denotes the ratio of the __________ to the __________ .
(A) area of a circle, circumference of the circle
(B) area of a circle, length of its diameter
(C) circumference of a circle, length of its radius
(D) circumference of a circle, length of its diameter

4. The value of π (pi) is a/an __________ .
(A) rational number
(B) irrational number
(C) integer
(D) complex number

5. If x2 + 1 = 0, then x = ?
(A) 1
(B) i
(C) ± 1
(D) ± i

1. B
2. A
3. D
4. B
5. D

6. The product of complex numbers (4,3) and (5,−6) is ?
(A) (18,3)
(B) (18,−3)
(C) (38,9)
(D) (38,−9)

7. (2,6) ÷ (4,2) = ?
(A) (1,1)
(B) (1,2)
(C) (2,1)
(D) (2,2)

8. (−i)−19 = ?
(A) 1
(B) −1
(C) i
(D) −i

9. The multiplicative identity of a complex number is ?
(A) (0,0)
(B) (1,0)
(C) (0,1)
(D) (1,1)

10. $\sqrt{-9}\times\sqrt{-9}=?$
(A) 9
(B) −9
(C) 9i
(D) −9i