CBSE 12TH MATHEMATICS - Online Test

Q1. If A, B be two square matrices such that |AB|=O, then
Answer : Option A
Explaination / Solution:

If A B be two square matrices such that AB=O, then, |AB|=O⇒|A||B|=O⇒either|A|=0,or|B|=0

Q2. In linear programming feasible region (or solution region) for the problem is
Answer : Option B
Explaination / Solution:

In linear programming feasible region (or solution region) for the problem is given by the common region determined by all the constraints including the non – negative constraints x ⩾ 0, y ⩾ 0

Q3. Let A = { 2 , 3 , 6 }. Which of the following relations on A are reflexive ?
Answer : Option A
Explaination / Solution:

 is a reflexive on A , because ( a,a ) ∈ R1  for each  a ∈ A

Q4. dx is equal to
Answer : Option D
Explaination / Solution:



Q5. Direction angles are
Answer : Option C
Explaination / Solution:

the angles are called direction angles, which the position vector makes with the positive x-axis ,y-axis and z-axis respectively

Q6. A black and a red dice are rolled. Find the conditional probability of obtaining a sum greater than 9, given that the black die resulted in a 5.
Answer : Option C
Explaination / Solution:

n(S)=36.
Let A = event of getting sum greater than 9.
= {(4,6),(5,5),(6,4),(5,6),(6,5),(6,6)}
And B = event of getting 5 on black die.
={(5,1),(5,2),(5,3),(5,4),(5,5),(5,6)}


Q7. The minimum value of sin x −− cos x is
Answer : Option B
Explaination / Solution:

(12)+(12)=2
Q8.  is equal to
Answer : Option D
Explaination / Solution:

  
Q9. The order of the equation  is
Answer : Option B
Explaination / Solution:

Since the equation has 2nd derivative as the highest derivative term.hence the order 2

Q10. If l, m and n are the direction cosines of a line, Direction ratios of the line are the numbers which are
Answer : Option C
Explaination / Solution:

If l, m and n are the direction cosines of a line, Direction ratios of the line are the numbers which are Proportional to the direction cosines of the line.