જો વિધેય f એ સમીકરણ  નું સમાધાન કરે (જ્યાં ) તો f(21) .......   from Mathematics ગણ, સંબંધ અને વિધેય

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Gujarati JEE Mathematics : ગણ, સંબંધ અને વિધેય

Multiple Choice Questions

11. જો  P = {1, 2, 3, 4,} Q = {a, b, c, d} હોય તો નીચેનાં જોડકાં જોડો : 

  • i - c, ii - a, iii - b

  • i - b, ii - c, ii - a

  • i - a, ii - b, iii - c

  • i - a, ii - c, iii - b


12.
જો f(x) એ દ્વિઘાત બહુપદી હોય તથા f(0) = 4 હોય તેમજ f(x+3) - f(x) 3x + 5,  x હોય, તો તે દ્વિઘાત બહુપદી હોય.
  • 3x2 + x +24

  • x2 + x + 24

  • 1 over 6 (3x2 + x + 24)
  • 1 half(x2 + 2x + 9)

13. જો f(x) = cos (log x) હોય, તો f(x), f(y) -bold minus bold 1 over bold 2 bold space open square brackets bold f open parentheses bold x over bold y close parentheses bold plus bold f bold left parenthesis bold xy bold right parenthesis close square brackets bold space bold equals bold space bold. bold. bold. bold. bold space bold.
  • x

  • x2

  • 0

  • 1


14. વાસ્તવિક વિધેય f(x) = square root of bold x to the power of bold 2 bold space bold plus bold space bold 6 bold x bold space bold plus bold space bold 10 end root નો વિસ્તાર ...... મળે. 
  • (-∞, 1)

  • [1, ∞]

  • R

  • (1, ∞)


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15. જો X = {4n - 3n - 1, n ∈ N} અને Y = {9 (n-1); n ∈ N} જ્યાં N = પ્રાકૃતિક સંખ્યાઓનો ગણ હોય તો X ∪ Y = ......... . 
  • X

  • Y - X

  • Y

  • N


16.
f(x) = ax2 + bx + c; x = 1, 2, 3 તથા g(x) = open curly brackets table attributes columnalign left end attributes row cell bold 3 bold x bold space bold plus bold 1 bold semicolon bold space bold x bold space bold equals bold space bold 2 bold comma bold 3 end cell row cell bold space bold space bold space bold space bold space bold space bold space bold space bold 3 bold semicolon bold space bold x bold space bold equals bold space bold 1 end cell end table close હોય તેમજ બંને વિધેયો સમાન હોય, તો નીચેનામાંથી કયું સત્ય બને ?
  • a = b = c = 1

  • straight a space equals space minus 1 half comma space straight b space equals space 11 over 2 comma space straight c space equals space minus 2
  • straight a space equals 11 over 2 comma space straight b space equals space minus 2 comma space straight c space equals 1 half
  • straight a space equals space 1 half comma space straight b space equals space 2 comma space straight c space equals space 11 over 2

17.
જો bold f bold left parenthesis bold x bold right parenthesis bold space bold equals bold space fraction numerator bold x bold minus bold 3 over denominator bold x bold plus bold 1 end fraction bold comma bold space bold x bold space bold not equal to bold space bold minus bold 1 હોય તો f(2016)(2015) = ......  જ્યાં f(2016)(x) એ f નું f સાથે 2016 વખત સંયોજિત વિધેય દર્શાવે છે.
  • 2017

  • 2014

  • 2016

  • 2015


18. જો f(x)=square root of bold log bold space bold left parenthesis bold sin bold space bold x bold right parenthesis end root હોય, તો વિધેય f નો મહત્તમ પ્રદેશ ......... હોય. 
  • left curly bracket left parenthesis 4 straight k space plus space 3 space right parenthesis space straight pi over 2 vertical line space straight k space element of space straight Z right curly bracket
  • left curly bracket space left parenthesis 4 straight k space minus 1 right parenthesis space straight pi over 2 vertical line space straight k space element of space straight Z right curly bracket
  • left curly bracket left parenthesis 4 straight k space plus space 1 right parenthesis space straight pi over 2 vertical line space straight k element of straight Z right curly bracket space
  • left curly bracket left parenthesis 4 straight k space plus space 3 space right parenthesis space straight pi over 4 vertical line space straight k space element of space straight Z right curly bracket

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19. જો વિધેય f એ સમીકરણ bold 3 over bold 10 bold space bold f bold left parenthesis bold x bold right parenthesis bold space bold plus bold space bold 2 over bold 10 bold f bold space open parentheses fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction close parentheses bold space bold equals bold space bold x bold space bold plus bold space bold 3 નું સમાધાન કરે (જ્યાં bold x bold space bold not equal to bold 1) તો f(21) .......  
  • 110

  • 116

  • 106

  • 96


B.

116

Tips: -

અહીં bold 3 over bold 10 bold f bold left parenthesis bold x bold right parenthesis bold space bold plus bold space bold 2 over bold 10 bold f bold space open parentheses fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction close parentheses bold space bold equals bold space bold x bold plus bold 3  આપેલ છે.

bold therefore bold space bold 3 bold f bold left parenthesis bold x bold right parenthesis bold space bold plus bold space bold 2 bold space bold f open parentheses fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction close parentheses bold space bold equals bold space bold 10 bold x bold space bold plus bold space bold 30              ... (1)

હવે x ને બદલે fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction લેતાં fraction numerator begin display style fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction end style bold plus bold 59 over denominator begin display style fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction end style bold minus bold 1 end fraction bold space bold equals bold space bold xહોવાથી

bold 3 bold f bold space open parentheses fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction close parentheses bold space bold plus bold space bold 2 bold space bold f bold left parenthesis bold x bold right parenthesis bold space bold equals bold space bold 10 bold space open parentheses fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction close parentheses bold space bold plus bold space bold 30

હવે સમીકરણ (1) ને 3 તથા સમીકરણ (2) ને 2 વડે ગુણી તે પછી પ્રાપ્ત સમીકરણ (1) માંથી સમીકરણ (2) બાદ કરતાં, 5f(x) = 30x - 20 open parentheses fraction numerator bold x bold plus bold 59 over denominator bold x bold minus bold 1 end fraction close parentheses bold space bold plus bold space bold 30
 
હવે ઉપર્યુક્ત પરિણામમાં x = 21 લેતાં,

5f(21) = 30 (21) + 30 - open parentheses fraction numerator bold 20 bold left parenthesis bold 21 bold plus bold 59 bold right parenthesis over denominator bold 20 end fraction close parentheses

          = 30 (21) + 30 - 80 = 580 

∴ f(21) = bold 580 over bold 5 bold space bold equals bold space bold 116


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20. f : (R -{-1} → R, f(x) = fraction numerator bold 1 bold minus bold x over denominator bold 1 bold plus bold x end fraction હોય તો, bold f bold space open parentheses fraction numerator bold x bold plus bold y over denominator bold 1 bold plus bold xy end fraction close parentheses = .......... 
  • f(x) + f(y) 

  • f(x)•f(y)

  • (f(x))2

  • f(x)/(f(y)


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