Subject

Mathematics

Class

CBSE Class 12

Pre Boards

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Sample Papers

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 Multiple Choice QuestionsShort Answer Type

21.

If straight x equals straight a space sint space and space straight y space equals space straight a open parentheses cost plus log space tan straight t over 2 close parentheses space find space fraction numerator straight d squared straight y over denominator dx squared end fraction

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22.

Evaluate: integral fraction numerator sin left parenthesis straight x minus straight a right parenthesis over denominator sin left parenthesis straight x plus straight a right parenthesis end fraction dx

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23.

Evaluate:
integral fraction numerator 5 straight x minus 2 over denominator left parenthesis 1 plus 2 straight x plus 3 straight x squared end fraction dx

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24.

Evaluate:
integral fraction numerator straight x squared over denominator left parenthesis straight x squared plus 4 right parenthesis left parenthesis straight x squared plus 9 right parenthesis end fraction dx


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25.

Evaluate: integral subscript 0 superscript 4 open parentheses open vertical bar straight x close vertical bar plus open vertical bar straight x minus 2 close vertical bar plus open vertical bar straight x minus 4 close vertical bar close parentheses dx

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26.

If straight a with rightwards arrow on top space and space straight b with rightwards arrow on top are two vectors such that open vertical bar straight a with rightwards arrow on top plus straight b with rightwards arrow on top close vertical bar equals open vertical bar straight a with rightwards arrow on top close vertical bar comma then prove that vector 2 straight a with rightwards arrow on top plus straight b with rightwards arrow on top is perpendicular to vector straight b with rightwards arrow on top.

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27.

Find the coordinates of the point, where the line fraction numerator straight x minus 2 over denominator 3 end fraction equals fraction numerator straight y plus 1 over denominator 4 end fraction equals fraction numerator straight z minus 2 over denominator 2 end fraction intersects the plane straight x minus straight y plus straight z minus 5 space equals space 0. Also find the angle between the line and the plane. 

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28.

Find the vector equation of the plane which contains the line of intersection of the planes. straight r with rightwards arrow on top. open parentheses straight i with hat on top plus 2 straight j with hat on top plus 3 straight k with hat on top close parentheses minus 4 space equals 0 and straight r with rightwards arrow on top. open parentheses 2 straight i with hat on top plus straight j with hat on top minus straight k with hat on top close parentheses plus 5 space equals 0 and which is perpendicular to the plane straight r with rightwards arrow on top. space open parentheses 5 straight i with hat on top plus 3 straight j with hat on top minus 6 straight k with hat on top close parentheses plus 8 space equals space 0

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29.

A speaks truth in 60% of the cases, while B in 90% of the cases. In what percent of cases are they likely to contradict each other in stating the same fact? In the cases of contradiction do you think, the statement of B will carry more weight as he speaks truth in more number of cases than A?


Let the probability that A and B speak truth be P(A) and P(B) respectively.
Therefore,  straight P left parenthesis straight A right parenthesis space equals space 60 over 100 space equals 3 over 5 space space and space straight P left parenthesis straight B right parenthesis space equals space 90 over 100 space equals space 9 over 10
A and B can contradict in stating a fact when one is speaking the truth and other is not speaking the truth.
Case 1:  A is speaking the truth and B is not speaking the truth.
Required space Probability space equals space straight P left parenthesis straight A right parenthesis space cross times space open parentheses 1 minus straight P left parenthesis straight B right parenthesis close parentheses space equals 3 over 5 cross times open parentheses 1 minus 9 over 10 close parentheses space equals 3 over 50.
Case 2: A is not speaking the truth and B is speaking the truth. 
Required Probability  = open parentheses 1 minus straight P left parenthesis straight A right parenthesis close parentheses space cross times space straight P left parenthesis straight B right parenthesis space equals space open parentheses 1 minus 3 over 5 close parentheses cross times 9 over 10 equals 9 over 25.

therefore space Percentage of cases in which they are likely to contradict in stating the same fact =
open parentheses 3 over 50 plus 9 over 25 close parentheses cross times 100 percent sign space space equals space open parentheses fraction numerator 3 plus 18 over denominator 50 end fraction close parentheses cross times 100 percent sign space equals 42 percent sign
From case 1, it is clear that is not necessary that the statement of B will carry more weight as he speaks truth in more number of cases than A.

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 Multiple Choice QuestionsLong Answer Type

30.

Using integration, find the area bounded by the curve x2 = 4y and the line x = 4y – 2.

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