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 


Let space cos to the power of negative 1 end exponent space equals space open parentheses straight a over straight b close parentheses space equals space straight x
Then comma space cos space straight x space equals space straight a over straight b
LHS colon
tan open curly brackets straight pi over 4 plus 1 half cos to the power of negative 1 end exponent straight a over straight b close curly brackets plus space tan space open parentheses straight pi over 4 minus 1 half cos to the power of negative 1 end exponent straight a over straight b close parentheses
equals space tan open parentheses straight pi over 4 space plus straight x over 2 close parentheses plus space tan space open parentheses straight pi over 4 minus straight x over 2 close parentheses
fraction numerator 1 plus space tan begin display style straight x over 2 end style over denominator 1 minus tan begin display style straight x over 2 end style end fraction space plus fraction numerator 1 minus space tan begin display style straight x over 2 end style over denominator 1 plus tan begin display style straight x over 2 end style end fraction
fraction numerator open parentheses 1 plus tan begin display style straight x over 2 end style close parentheses squared plus open parentheses 1 minus tan begin display style straight x over 2 end style close parentheses squared over denominator 1 minus tan squared begin display style straight x over 2 end style end fraction
space equals space 2 open parentheses fraction numerator 1 plus tan squared begin display style straight x over 2 end style over denominator 1 minus tan squared begin display style straight x over 2 end style end fraction close parentheses
space equals space fraction numerator 2 over denominator cos space straight x end fraction space open square brackets because space cos space 2 straight x space equals space fraction numerator 1 minus tan squared straight x over denominator 1 plus space tan squared space straight x end fraction close square brackets
space equals space fraction numerator 2 straight b over denominator straight a end fraction space equals space RHS
Hence space proved
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9.

Using properties of determinants, prove that 

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10.

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

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