Mathematics - Online Test

Q1. The line touches the curve at the point
Answer : Option C
Explaination / Solution:



Q2. The sum of all 2-digited numbers which leave remainder 1 when divided by 3 is
Answer : Option D
Explaination / Solution:



Q3. If the two lines of regression are y = 3x – 5 and y = 2x – 4 , then ρ(X,Y) is equal to
Answer : Option A
Explaination / Solution:

let us assume that y = 3x – 5 and y = 2x – 4 are lines of regression of x on y and y on x respectively,therefore



but sign of ρ is same as  and 

therefore 


Q4. The positive value of the parameter a for which the area of the figure bounded by y = sin ax , y = 0 , x =  is 3 is equal to
Answer : Option B
Explaination / Solution:



Q5. Let A be the set of all students of a boys school. The relation R on A is given by R = {(a, b) : a is sister of b} is
Answer : Option A
Explaination / Solution:

Because , the relation is defined over the set A be the set of all students of a boys school.

Q6. If the entries in a 3 x 3 determinant are either 0 or 1 , then the greatest value of this determinant is :
Answer : Option C
Explaination / Solution:

Greatest value = 2 .

Q7. The lines ix + my + n = 0 , mx + ny + l = 0 and nx + ly +m = 0 are concurrent if
Answer : Option B
Explaination / Solution:

The required condition for concurrency is a3(b1c2 - b2c1) + b3(c1a2 - c2a1) + c3(a1b2 - a2b1) = 0

Here a1 = l, a=m, a3 = n and b1 = m, b2 = n, b3 = l and c1 = n, c2 = l and c3 = m

Substituting the values  we get

n(ml - n2) + l(nm - l2) +m(ln - m2) = 0

This implies l3 + m3 + n3 - 3lmn = 0

That is (l + m+ n)(l2 + m2 + n2 -lm -mn - nl) = 0

This implies l + m + n = 0


Q8. The contrapositive of the statement “ if  then I get first class” is
Answer : Option C
Explaination / Solution:

p:

q:I get first class

the contrapositive of . hence the answer is If I do not get a first class , then 


Q9. is equal to
Answer : Option D
Explaination / Solution:


Q10. Write down a unit vector in XY-plane, making an angle of 30° with the positive direction of x-axis.
Answer : Option D
Explaination / Solution:

Let be a unit vector in XY plane,making angle 300 with positive X axis,so we have the vector as 

 is the required vector.