હોય, તો f-1(x) = .........  (સ્વીકારી લો કે f-1 નું અસ્તિત્વ છે.) from Mathematics ગણ, સંબંધ અને વિધેય

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Gujarati JEE Mathematics : ગણ, સંબંધ અને વિધેય

Multiple Choice Questions

31. {-2, 2} → {1, 3} પર એક-એક સંગતતા ધરાવતા બે ભિન્ન વિધેયો નીચેનામાંથી કયા હોઈ શકે ? straight x over 2 plus 2
  • y = ±

  • y = ±x + 4

  • y = x ± 2

  • y = ± x ± 2


32.
જો f: R - {-3} →R - {1} પર વ્યાખ્યાયિત વિધેય, f(x) = fraction numerator bold x bold plus bold 2 over denominator bold x bold plus bold 3 end fraction નું પ્રતિવિધેય અસ્તિત્વ ધરાવતો x ∈ ........... માટે, f-1(x) > 0 મળે.
  • open parentheses 2 over 3 comma space 1 close parentheses
  • open parentheses negative infinity comma 2 over 3 close parentheses
  • left parenthesis 1 comma space infinity right parenthesis
  • શક્ય નથી.


33.
f:R-[-1, ∞] પર f(x) = (x + 1)2-1 દ્વારા વ્યાખ્યાયિત વિધેય માટે જો S = {x| f(x) = f-1(x)} હોત, તો x = .......... મળે.
  • {0, 1, -1}

  • {0, -1}

  • up diagonal strike 0
  • open curly brackets 0 comma space 1 comma space fraction numerator negative square root of 3 plus square root of 31 over denominator 2 end fraction comma space fraction numerator negative square root of 3 minus square root of 31 over denominator 2 end fraction close curly brackets

34. જો d: R →R, f(x) = sin x અને g : (1, ∞) →R, g(x) = square root of bold x to the power of bold 2 bold space bold minus bold space bold 1 end root હોય, તો (gof) (x) = ...... 
  • cos space x
  • sin space square root of x squared space minus space 1 end root
  • square root of sin space left parenthesis straight x squared space minus space 1 right parenthesis end root
  • અવ્યાખ્યાયિત


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35.
bold f bold space bold colon bold space bold R bold space bold rightwards arrow bold space bold left curly bracket bold y bold space bold vertical line bold space bold vertical line bold y bold vertical line bold less than bold 1 bold comma bold space bold y bold element of bold R bold right curly bracket bold comma bold space bold f bold left parenthesis bold x bold right parenthesis bold space bold equals bold space fraction numerator bold 10 to the power of bold x bold minus bold 10 to the power of bold minus bold x end exponent over denominator bold 10 to the power of bold x bold space bold plus bold space bold 10 to the power of bold minus bold x end exponent end fraction હોય, તો f-1(x) = .........  (સ્વીકારી લો કે f-1 નું અસ્તિત્વ છે.)
  • 1 half space log subscript 10 space open parentheses fraction numerator 1 plus straight x over denominator 1 minus straight x end fraction close parentheses
  • 1 fourth space log subscript 10 space open parentheses fraction numerator 2 x over denominator 2 minus x end fraction close parentheses
  • 1 half space log subscript 10 space left parenthesis 2 x minus 1 right parenthesis
  • log subscript 10 space left parenthesis 2 minus straight x right parenthesis

A.

1 half space log subscript 10 space open parentheses fraction numerator 1 plus straight x over denominator 1 minus straight x end fraction close parentheses

Tips: -

અહીં, f : R → {y | |y|<1, y ∈ R} ;  x, x ∈ R, f(x) = fraction numerator bold 10 to the power of bold x bold space bold minus bold space bold 10 to the power of bold minus bold x end exponent over denominator bold 10 to the power of bold x bold space bold plus bold space bold 10 to the power of bold minus bold x end exponent end fraction આપેલ છે.

bold f bold left parenthesis bold x bold right parenthesis bold space bold equals bold space fraction numerator bold 10 to the power of bold x bold space bold minus bold space bold 10 to the power of bold minus bold x end exponent over denominator bold 10 to the power of bold x bold space bold plus bold space bold 10 to the power of bold minus bold x end exponent end fraction bold space bold equals bold space bold yલેતાં,

bold therefore bold space fraction numerator bold 10 to the power of bold x bold space bold minus bold space bold 10 to the power of bold minus bold x end exponent bold space bold plus bold space bold 10 to the power of bold x bold space bold plus bold space bold 10 to the power of bold minus bold x end exponent over denominator bold 10 to the power of bold x bold space bold plus bold space bold 10 to the power of bold minus bold x end exponent bold space bold minus bold space bold 10 to the power of bold x bold space bold plus bold space bold 10 to the power of bold minus bold x end exponent end fraction bold space bold equals bold space fraction numerator bold 1 bold plus bold y over denominator bold 1 bold minus bold y end fraction


bold therefore bold space fraction numerator bold 2 bold space open parentheses bold 10 to the power of bold x close parentheses over denominator bold 2 bold space bold left parenthesis bold 10 to the power of bold minus bold x end exponent bold right parenthesis end fraction bold space bold equals bold space fraction numerator bold 1 bold plus bold y over denominator bold 1 bold minus bold y end fraction bold.  
આથી bold 10 to the power of bold 2 bold x end exponent bold space bold equals bold space fraction numerator bold 1 bold plus bold y over denominator bold 1 bold minus bold y end fraction bold comma bold space સ્પષ્ટ છે |y} < 1.

∴ 2x = log10 open parentheses fraction numerator bold 1 bold plus bold y over denominator bold 1 bold minus bold y end fraction close parentheses

bold therefore bold space bold x bold space bold equals bold space bold 1 over bold 2 bold space bold log subscript bold 10 bold space open parentheses fraction numerator bold 1 bold plus bold y over denominator bold 1 bold minus bold y end fraction close parentheses

∴  bold y bold comma bold space bold vertical line bold y bold vertical line bold space bold less than bold space bold 1 bold comma bold space bold f bold left parenthesis bold x bold right parenthesis bold space bold equals bold y bold space bold rightwards double arrow bold space bold x bold space bold equals bold space bold f to the power of bold minus bold 1 end exponent bold space bold left parenthesis bold y bold right parenthesis

bold therefore bold space bold f to the power of bold minus bold 1 end exponent bold space bold colon bold space bold left curly bracket bold y bold space bold vertical line bold space bold vertical line bold y bold vertical line bold less than bold 1 bold comma bold space bold y bold element of bold R bold right curly bracket bold space bold rightwards arrow bold space bold R bold comma bold space bold f to the power of bold minus bold 1 end exponent bold space bold left parenthesis bold y bold right parenthesis bold space bold equals bold space bold 1 over bold 2 bold space bold log subscript bold 10 bold space open parentheses fraction numerator bold 1 bold plus bold y over denominator bold 1 bold minus bold y end fraction close parentheses

bold therefore bold space bold f to the power of bold minus bold 1 end exponent bold space bold left parenthesis bold x bold right parenthesis bold space bold equals bold space bold 1 over bold 2 bold space bold log subscript bold 10 bold space open parentheses fraction numerator bold 1 bold plus bold x over denominator bold 1 bold minus bold x end fraction close parentheses


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36. વિધેય f(x) = log4 [log5 {log3, (18x - x2 - 77}] નો મહત્તમ પ્રદેશ ........ મળે.
  • (8, 10)

  • (0, 10)

  • (10, 12)

  • (4, 5)


37.
બહુપદી વિધેય f(x) = xn + 1 એ f(x) f open parentheses bold 1 over bold x close parentheses bold space bold equals bold space bold f bold left parenthesis bold x bold right parenthesis bold space bold plus bold space bold f open parentheses bold 1 over bold x close parentheses શરત સંતોષે છે. જો f(12) = 1729 હોય, તો f(15) = ............ .x ∈ R
  • 3357

  • 3376

  • 2075

  • 1001


38. વિધેય f(x) = 9x - 3x + 1 નો વિસ્તાર ......... હોય.
  • (0, ∞)

  • (-∞, 0)

  • (-∞, ∞)

  • open square brackets 3 over 4 comma space infinity close square brackets

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39. જો f(x) = sin2 x + sin2 open parentheses bold x bold plus bold pi over bold 3 close parentheses bold space bold plus bold space bold italic c bold italic o bold italic s bold space bold italic x bold space bold. bold space bold italic c bold italic o bold italic s bold space open parentheses bold x bold plus bold pi over bold 3 close parentheses bold space તથા g bold 5 over bold 4 = 1 હોય તો (gof) (x) = ............ . 
  • 1

  • 4 over 5
  • 5 over 4
  • અવ્યાખ્યાયિત


40.
વિધેય f : A → R, f(x) = bold log subscript begin inline style fraction numerator bold x bold minus bold 2 over denominator bold x bold plus bold 3 end fraction end style end subscript bold 2 તથા g : B → R, g(x) = fraction numerator bold 1 over denominator square root of bold x to the power of bold 2 bold space bold minus bold 9 end root end fraction હોય, તો x ની કઈ કિંમતો માટે વિધેય bold f over bold g અસ્તિત્વ ધરાવે ?
  • (-3, 2)

  • (-∞, -3) ∪ (3, ∞) 

  • [2,3]

  • [-3, -2]


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