The graph of a quadratic function is always a …………… , A ) Parabola , B ) Circle , C ) Ellipse , D ) None of these ,

 

1 )  The graph of a quadratic function is always a …………… ,

A ) Parabola ,                                 B ) Circle ,

C ) Ellipse ,                                      D ) None of these ,

Correct Answer : -   A ) Parabola ,

 

2 )   i.(j x k) = ……………. ,

A )  0  ,                                             B )  1  ,

C )  90 ,                                           D ) None of these ,

Correct Answer : -   B )  1  ,

Solution : -

For dot product : - 

 i . i = 1     ,        j . j = 1      ,           k . k =1  .

Other than that , it will be equals to zero  .

For cross product : -

i x j = k     ,         j x k = i      ,          k . i = j  .

So ,

  i . ( j x k )  =  i . ( i )  =  1  ,  Answer .

3 )  Four roots of unity are : -   (1, -1, i, -i) .  

 

4 )   The sum of squares of two conjugate complex no. is always a ………….. ,

A ) Real no.  ,                                  B )  Complex no.  ,

C ) Imaginary no.  ,                          D ) None of these ,

Correct Answer : -  A ) Real no.  ,

 

5 )  Two excavators dig 10m² of earth in first day , 15m² in 2^nd day  , 20m² in third day. So what total would be in 9^th day?

A ) 261  ,                                          B ) 268  ,

C ) 271  ,                                         D ) None of these ,

Correct Answer : -   A ) 261  ,

Solution:-   

Given Data : -

·        a₁ = 10  ,

·        d = 5m² .

Formula : -     

Sn = (n\2){2a + (n-1)d } ,

Ø   S₉ = (9/2){ 2(9) + (9-1)5 }  ,

Ø   S₉ = (9/2){ 18 + 40 }  ,

Ø   S₉ = (9/2){ 58 }  ,

Ø    S₉ = (9)(29)  ,

Ø    S₉= 261   ,   Answer.

 

6 )  If order of A is (m x n) and order of B is (n x p). So order of AB?  

A ) m x n ,                                        B ) m x p  ,

C ) p x n ,                                 D ) None of these ,

Correct Answer : -   B ) m x p  ,

7 )  When two rows or two columns of a matrix is equal , so its determinant [A] will be ………. ,

A ) Zero  ,                                                B ) Finite ,

C ) Infinite ,                                      D ) None of these ,

Correct Answer : -   A ) Zero  ,

Explanation : -

When two rows or two columns of a matrix is equal , so its determinant [A] will be zero and its inverse A^-1 will be Infinite .

 

8 )  When two sets are equal, so the result of their intersection and union  will be …………. ,

A ) Same ,                                               B ) Different ,

C ) infinite ,                                      D ) None of these ,

Correct Answer : - A ) Same ,

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