Subject

Mathematics

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

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 Multiple Choice QuestionsShort Answer Type

1.

If A is a 3 × 3 invertible matrix, then what will be the value of k if det(A–1) = (det A)k.

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2.

Determine the value of the constant ‘k’ so that the function  is continuous at x = 0.

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3.

If a line makes angles 90° and 60° respectively with the positive directions of x and y axes, find the angle which it makes with the positive direction of the z-axis.

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4.

Show that all the diagonal elements of a skew symmetric matrix are zero.

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5.
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6.

The volume of a sphere is increasing at the rate of 3 cubic centimetres per second. Find the rate of increase of its surface area, when the radius is 2 cm.

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7.

Show that the function f(x) = 4x3 – 18x2 + 27x – 7 is always increasing on R.

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8.

Prove that 

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9.

Using properties of determinants, prove that 


open vertical bar table row cell straight x space end cell cell straight x plus straight y space end cell cell straight x plus 2 straight y space end cell row cell straight x plus 2 straight y space end cell cell straight x space end cell cell straight x plus straight y end cell row cell straight x plus straight y space end cell cell straight x plus 2 straight y space end cell cell straight x space end cell end table close vertical bar
Applying space straight R subscript 1 rightwards arrow straight R subscript 1 space plus straight R subscript 2 space plus space straight R subscript 3 space we space get colon
open vertical bar table row cell 3 left parenthesis straight x plus straight y right parenthesis end cell cell 3 left parenthesis straight x plus straight y right parenthesis end cell cell 3 left parenthesis straight x plus straight y right parenthesis end cell row cell straight x plus 2 straight y end cell straight x cell straight x plus straight y end cell row cell straight x plus straight y end cell cell straight x plus 2 straight y end cell straight x end table close vertical bar
space equals space 3 left parenthesis straight x plus straight y right parenthesis space open vertical bar table row 1 1 1 row cell straight x plus 2 straight y end cell straight x cell straight x plus straight y end cell row cell straight x plus straight y end cell cell straight x plus 2 straight y end cell straight x end table close vertical bar
Applying space straight C subscript 1 rightwards arrow straight C subscript 1 minus straight C subscript 2 space and space straight C subscript 2 space rightwards arrow straight C subscript 2 minus straight C subscript 3 space we space get colon
3 left parenthesis straight x plus straight y right parenthesis space open vertical bar table row 0 0 1 row cell 2 straight y end cell cell negative straight y end cell cell straight x plus straight y end cell row cell negative straight y end cell cell 2 straight y end cell straight x end table close vertical bar
equals space 3 left parenthesis straight x plus straight y right parenthesis open vertical bar table row cell 2 straight y end cell cell negative straight y end cell row cell negative straight y end cell cell 2 straight y end cell end table close vertical bar space equals space 3 left parenthesis straight x plus straight y right parenthesis left parenthesis 4 straight y squared minus straight y squared right parenthesis space equals space 9 straight y squared space left parenthesis straight x plus straight y right parenthesis
space RHS equals space LHS
Hence space Proved
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10.

Let find a matrix D such that CD – AB = O.

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