ECAT Pre Engineering Mathematic MCQ Test With Answer for Chapter 1 (Number System)

The product of complex numbers (a,b) and (c,d) is

• (ac, bd) A
• (ac-bd, ad+bc) B
• (ab,cd) C
• (ac+bd,ad-bc) D

If in a set of real no a is multiplicative identity then

• a,a = a² A
• a,a = 1 B
• a,a = 0 C
• None of these D

The equation |x + 4| = x has solution

• x = -2 A
• x = 2 B
• x = -4 C
• x = 4 D

What is the conjugate of -6 -i?

• -6 +i A
• 6+i B
• -6 -i C
• 6 -i D

In R, the multiplicative inverse of a is

• 0 A
• 1 B
• -a C
• 1/a D

∀a,b ε R, ab = be is a

• Commutative law of multiplication A
• Closure law of multiplication B
• Associative law of multiplication C
• Multiplicative identity D

For any real numbers x,y,xy=o ⇒

• x ≠ 0 ∧ y ≠ 0 A
• x = 0 ∨ y = 0 B
• x = 0 C
• y = 0 D

Gooch crucible is made of :

• Brass. A
• Porcelain. B
• Bronze. C
• Gold. D

Decimal part of irrational number is

• Terminating A
• Repeating only B
• Neither repeating nor terminating C
• Repeating and terminating D

Every real number is

• a positive integer A
• a rational number B
• a negative integer C
• a complex number D

i =

• 
  A
• 
  B
• 
  C
• 
  D

• z is purely imaginary A
• a is any complex number B
• z is real C
• None of these D

Every natural number is

• A prime number A
• An irrational number B
• An integer C
• An even number D

• 
  A
• 
  B
• 
  C
• 
  D

• 
  A
• 
  B
• 
  C
• 
  D

• Associative property of addition A
• Associative property of multiplication B
• Commutative property of addition C
• Commutative property of multiplication D

• (a + b)c = a . c + bc A
• a + b = b + a B
• (a + b) + c = a + (b + c) C
• a(b+ c) = ab + ac D

√25 is a number

• Rational A
• Irrational B
• Natural C
• Odd D

If z₁ =√-36 ,z₂ =√-25,z3 =√-16 then

• 15 A
• 15i B
• -15i C
• -15 D

• Commutative law of addition A
• Associative law of addition B
• Additive identity C
• Additive inverse D

The multiplicative inverse of 1 is

• 1 A
• -1 B
• 0 C
• Does not exist D

The conjugate of √5 i is

• √5 A
• -√5 i B
• i C
• 5i D

A prime number can be a factor of a square only if it occurs in the square at least

• Once A
• Thirce B
• Twice C
• None of these D

If z₁ = (a,b), z₂=(c,d), then z₁ z₂ = -------------------

• (ac,bd) A
• (ac+bd, ad-bc) B
• (ac-bd , ad+bc) C
• (ac-bd , ad-bc) D

14 is not a

• Prime number A
• Whole number B
• Even number C
• Real number D

√11 is

• an irrational number A
• Rational number B
• odd number C
• Negative number D

If z₁= 2 + 6i and z₂= 3 + 7i, then which expression defines the product of z₁and z₂?

• 36 + (-32)i A
• -36 + 32i B
• 6 + (-11)1 C
• 0, +(-12)i D

The multiplicative inverse of (a,b) is

• 
  A
• 
  B
• 
  C
• 
  D

• Associative law of addition A
• Commutative law of addition B
• Additive identity C
• Closure law of addition D

The set { 1 , -1} is closed w.r.t.

• Addition A
• Multiplications B
• Subtraction C
• None of these D