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

21.

The scalar product of the vector straight a with rightwards arrow on top equals space straight i with hat on top plus straight j with hat on top plus straight k with hat on top with a unit vector along the sum of vectors straight b with rightwards arrow on top equals 2 straight i with hat on top plus 4 straight j with hat on top minus 5 straight k with hat on top space space and space straight c with rightwards arrow on top space equals space straight lambda straight i with hat on top plus 2 straight j with hat on top plus 3 straight k with hat on top is equal to one. Find the value of straight lambda and hence find the unit vector along straight b with rightwards arrow on top plus straight c with rightwards arrow on top.

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22. Evaluate colon
integral subscript 0 superscript straight pi fraction numerator 4 straight x space sinx over denominator 1 plus cos squared straight x end fraction dx


We need to evaluate the integral

straight I space equals space integral subscript 0 superscript straight pi fraction numerator 4 straight x space sinx over denominator 1 plus cos squared straight x end fraction dx... left parenthesis 1 right parenthesis
Using space the space property space integral straight f left parenthesis straight a minus straight x right parenthesis dx equals integral straight f left parenthesis straight x right parenthesis dx comma space we space have
straight I equals space integral subscript 0 superscript straight pi fraction numerator 4 left parenthesis straight pi minus straight x right parenthesis space sin left parenthesis straight pi minus straight x right parenthesis over denominator 1 plus cos squared left parenthesis straight pi minus straight x right parenthesis end fraction dx
rightwards double arrow space space straight I space equals space integral subscript 0 superscript straight pi fraction numerator 4 straight pi space sinx over denominator 1 plus cos squared straight x end fraction dx minus integral subscript 0 superscript straight pi fraction numerator 4 straight x space sinx over denominator 1 plus cos squared straight x end fraction dx... left parenthesis 2 right parenthesis
Adding space equations space left parenthesis 1 right parenthesis space and space left parenthesis 2 right parenthesis comma space we space have comma

rightwards double arrow 2 straight I space equals space integral subscript 0 superscript straight pi fraction numerator 4 straight x space sinx over denominator 1 plus cos squared straight x end fraction dx space plus space integral subscript 0 superscript straight pi fraction numerator 4 πsinx over denominator 1 plus cos squared straight x end fraction dx minus integral subscript 0 superscript straight pi fraction numerator 4 straight x space sinx over denominator 1 plus cos squared straight x end fraction dx
rightwards double arrow 2 straight I space equals space integral subscript 0 superscript straight pi fraction numerator 4 straight pi space sinx over denominator 1 plus cos squared straight x end fraction dx
rightwards double arrow 2 straight I space equals space 4 straight pi integral subscript 0 superscript straight pi fraction numerator sinx over denominator 1 plus cos squared straight x end fraction dx

Substitute space straight t space equals space cosx semicolon space dt space equals space minus sinxdx
when space straight x space equals space 0 comma space space straight t space equals 1
when space straight x space equals space straight pi comma space straight t equals negative 1
rightwards double arrow 2 straight I space equals space 4 straight pi integral subscript 1 superscript negative 1 end superscript fraction numerator left parenthesis negative 1 right parenthesis dt over denominator 1 plus straight t squared end fraction
rightwards double arrow space straight I space equals space 2 straight pi integral subscript negative 1 end subscript superscript 1 space fraction numerator dt over denominator 1 plus straight t squared end fraction
rightwards double arrow straight I space equals 2 cross times 2 straight pi integral subscript 0 superscript 1 fraction numerator dt over denominator 1 plus straight t squared end fraction
rightwards double arrow straight I space equals space 2 cross times 2 straight pi open parentheses tan to the power of negative 1 end exponent straight t close parentheses subscript 0 superscript 1
rightwards double arrow space straight I equals space 4 straight pi space tan to the power of negative 1 end exponent left parenthesis 1 right parenthesis
rightwards double arrow space straight I equals 4 straight pi cross times straight pi over 4 equals straight pi squared

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23.

Evaluate:
integral fraction numerator straight x plus 2 over denominator square root of straight x squared plus 5 straight x plus 6 end root end fraction dx

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24.

An experiment succeeds thrice as often as it fails. Find the probability that in the next five trials, there will be at least 3 successes.

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25. If space straight y space equals space Pe to the power of ax plus Qe to the power of bx show that
straight d to the power of 2 straight y end exponent over dx squared minus left parenthesis straight a plus straight b right parenthesis dy over dx plus aby space equals 0
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26. If space straight x equals cost left parenthesis 3 minus 2 cos squared straight t right parenthesis space and space straight y equals sint left parenthesis 3 minus 2 sin squared straight t right parenthesis comma space find space the space value space of space dy over dx at space straight t equals straight pi over 4.
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27.

Find the particular solution of the differential equation log open parentheses dy over dx close parentheses equals 3 straight x plus 4 straight y comma space given space that space straight y space equals space 0 comma space when space straight x equals space 0.

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28.

Find the value of p, so that the lines:
are perpendicular to each other. Also find the equations of a line passing through a point (3, 2, -4) and parallel to line l1.

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 Multiple Choice QuestionsLong Answer Type

29.

Find the equation of the plane through the line of intersection of the planes x + y + z = 1 and 2x + 3y + 4z = 5 which is perpendicular to the plane x- y + z = 0. Also find the distance of the plane obtained above, from the origin.

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30.

Find the distance of the point (2, 12, 5) from the point of intersection of the line 
straight r with rightwards arrow on top equals 2 straight i with hat on top minus 4 straight j with hat on top plus 2 straight k with hat on top plus straight lambda open parentheses 3 straight i with hat on top plus 4 straight j with hat on top plus 2 straight k with hat on top close parentheses space and space the space plane space straight r with rightwards arrow on top. open parentheses straight i with hat on top minus 2 straight j with hat on top plus straight k with hat on top close parentheses equals 0.

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