O કેન્દ્રવાળો ઉપવલય છે પર P કોઈ એક બિંદુ છે. કેન્દ્ર 0 માંથી દોરેલ P પરના સ્પર્શક પર દોરેલ લંબનો લંબપાદ N છે. ધારો કે Amax એ ∆OPN નું મહત્તમ ક્ષેત્રફળ છે.  ની કિંમત .....  from Mathematics લક્ષ-સાતત્ય અને વિકલન

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Gujarati JEE Mathematics : લક્ષ-સાતત્ય અને વિકલન

Multiple Choice Questions

141.
વક્ર y = [| sinx | + | cosx |] અને x2 + y2 = 5 વચ્ચેના ખૂણાનું માપ ........ છે. જ્યાં [.] એ પૂર્ણાંક ભાગ વિધેય છે. 
  • bold cos to the power of bold minus bold 1 end exponent open parentheses fraction numerator bold 2 over denominator square root of bold 5 end fraction close parentheses
  • bold tan to the power of bold minus bold 1 end exponent bold space bold 3 bold space
  • bold pi over bold 6 bold space
  • bold pi over bold 2

142.
જો a, b > 0 તો y = fraction numerator bold b to the power of bold 2 over denominator bold a bold minus bold x end fraction bold space bold plus bold space bold a to the power of bold 2 over bold x, 0 < x < a નું ન્યુનતમ મૂલ્ય ...... થાય. 
  • fraction numerator bold ab over denominator bold a bold plus bold b end fraction
  • bold 1 over bold a bold plus bold 1 over bold b
  • fraction numerator bold left parenthesis bold a bold plus bold b bold right parenthesis to the power of bold 2 over denominator bold a end fraction
  • fraction numerator begin display style bold a bold space bold plus bold space bold b end style over denominator begin display style bold a end style end fraction

143. bold વ િ ધ ે ય bold space bold g bold left parenthesis bold x bold right parenthesis bold space bold equals bold space bold tanx bold. bold space bold ex bold space bold e to the power of bold x to the power of bold 2 end exponent bold space fraction numerator bold log bold left parenthesis bold pi bold space bold plus bold space bold x bold right parenthesis over denominator bold log bold left parenthesis bold e bold space bold plus bold space bold x bold right parenthesis bold space end fraction bold left parenthesis bold x bold greater-than or slanted equal to bold 0 bold right parenthesis bold space bold એ
  • open square brackets 0 comma straight pi over e close square brackets પર વધતું તથા open square brackets bold pi over bold e bold comma bold infinity close square brackets પર ઘટતું વિધેય છે.

  • open square brackets bold 0 bold comma bold pi over bold e close square brackets પર ઘટતું તથા open square brackets bold pi over bold e bold comma bold infinity close square bracketsપર વધતું વિધેય છે.
  • [0, ∞]પર વધતું વિધેય છે. 

  • [0, ∞]પર ઘટતું વિધેય છે.


144.
જો α β અને γ એ સમીકરણ x3 + x2 - 5x - 1 = 0 નાં બીજ હોય, તો [α] +  [β] +  [γ] = ........ 
  • 2

  • -3

  • 4

  • 5


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145.

નીચેનામાંથી કયા અંતરાલમાં a ની કિંમત આવે તો
f(x) = sinx - asin2x - bold 1 over bold 3sinx3 + 2ax એ R પર વધતું વિધેય થાય ?

  • [0, ∞) 

  • [1, ∞)

  • [0, ∞) 

  • bold left square bracket bold space bold 1 over bold 2 bold comma bold space bold infinity bold right parenthesis

146. bold વ િ ધ ે ય bold space bold f bold left parenthesis bold x bold right parenthesis bold space bold equals bold space open curly brackets table row cell bold left parenthesis bold x bold space bold plus bold space bold 1 bold right parenthesis bold 3 bold comma bold space end cell row cell bold x to the power of bold 2 over bold 3 end exponent bold minus bold 1 bold comma bold space end cell row cell bold minus bold left parenthesis bold x bold space bold minus bold 1 bold right parenthesis end cell end table close bold space bold space bold space table attributes columnalign left end attributes row cell bold minus bold 2 bold space bold less than bold x bold space bold less-than or slanted equal to bold space bold minus bold space bold 1 end cell row cell bold minus bold 1 bold space bold less than bold space bold x bold space bold less-than or slanted equal to bold space bold 1 end cell row cell bold 1 bold space bold less than bold space bold X bold less than bold space bold 2 end cell end table

ને કેટલાં બિંદુઓએ સ્થાનીય મહત્તમ ન્યુનત્તમ મૂલ્યોનું અસ્તિત્વ હોય ? 
  • 1

  • 2

  • 3

  • 4


147.

જો f(x)= અને g(x) = , 0<x<1, તો આ અંતરાલમાં

  • f(x) વધતું વિધેય છે અને g(x) ઘટતું વિધેય છે.

  • g(x) વધતું વિધેય છે અને f(x) ઘટતું વિધેય છે.

  • f(x) અને g(x) બંને વધતાં વિધેય છે. 

  • f(x) અને g(x) બંને ઘટતાં વિધેય છે. 


148.
વક્ર 4x2 + a2y2 = 4a2, 4 < a2  < 8 પરનું ......... બિંદુ એ (0, -2) થી સૌથી દૂરનું બિંદુ છે. 
  • (0, 2) 

  • (0, -2)

  • (0, 1) 

  • (0, -1) 


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149.
O કેન્દ્રવાળો ઉપવલય છેbold x to the power of bold 2 over bold y to the power of bold 2 bold space bold plus bold space bold y to the power of bold 2 over bold b to the power of bold 2 bold space bold equals bold space bold 1 પર P કોઈ એક બિંદુ છે. કેન્દ્ર 0 માંથી દોરેલ P પરના સ્પર્શક પર દોરેલ લંબનો લંબપાદ N છે. ધારો કે Amax એ ∆OPN નું મહત્તમ ક્ષેત્રફળ છે. fraction numerator bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 over denominator bold A subscript bold max end fraction ની કિંમત ..... 
  • 1

  • 2

  • 4

  • 8


C.

4

Tips: -

બિંદુ P ના યામ (acosθ, bsinθ) લો.

bold therefore bold space open parentheses bold dy over bold dx close parentheses subscript bold p bold space bold equals bold space fraction numerator bold bcosθ over denominator bold minus bold a bold space bold sinθ end fraction bold space bold equals bold space fraction numerator bold minus bold b over denominator bold a end fraction bold cotθ


P બિંદુએ સ્પર્શકનું સમીકરણ


bxcosθ + aysinθ = ab


કાટકોણ ∆OPNમાં


PN2 - OP2 - ON2 

bold equals bold space bold a bold 2 bold cos bold 2 bold theta bold space bold plus bold space bold b bold 2 bold sin bold 2 bold theta bold space bold minus bold space fraction numerator bold a to the power of bold 2 bold b to the power of bold 2 over denominator bold a to the power of bold 2 bold sinθ bold space bold plus bold space bold b to the power of bold 2 bold cos to the power of bold 2 bold theta end fraction bold space

bold equals bold space fraction numerator bold a to the power of bold 4 bold sin to the power of bold 2 bold θcos to the power of bold 2 bold theta bold plus bold b to the power of bold 4 bold sin to the power of bold 2 bold θcos to the power of bold 2 bold theta bold space bold plus bold space bold a to the power of bold 2 bold b to the power of bold 2 bold left parenthesis bold sin to the power of bold 4 bold theta bold space bold plus bold space bold cos to the power of bold 4 bold theta bold right parenthesis bold space bold minus bold space bold a to the power of bold 2 bold b to the power of bold 2 bold left parenthesis bold sin to the power of bold 2 bold theta bold space bold plus bold space bold cos to the power of bold 2 bold theta bold right parenthesis to the power of bold 2 over denominator bold a to the power of bold 2 bold sin to the power of bold 2 bold theta bold space bold plus bold space bold b to the power of bold 2 bold cos to the power of bold 2 bold theta end fraction

bold equals bold space fraction numerator open parentheses bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 close parentheses to the power of bold 2 bold space bold sin to the power of bold 2 bold θcos to the power of bold 2 bold theta over denominator bold a to the power of bold 2 bold sin to the power of bold 2 bold theta bold space bold plus bold space bold b to the power of bold 2 bold cos to the power of bold 2 bold theta end fraction

bold therefore bold space bold PN bold space bold equals bold space fraction numerator open parentheses bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 close parentheses to the power of bold 2 bold space bold sin to the power of bold 2 bold θcos to the power of bold 2 bold theta over denominator square root of bold a to the power of bold 2 bold sin to the power of bold 2 bold theta bold space bold plus bold space bold b to the power of bold 2 bold cos to the power of bold 2 bold theta end root end fraction bold space

bold A bold space bold equals bold space bold 1 over bold 2 bold space bold PN bold space bold cross times bold space bold ON bold space bold equals bold space fraction numerator bold ab bold left parenthesis bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 bold right parenthesis bold space bold sinθcosθ over denominator bold 2 bold left parenthesis bold a to the power of bold 2 bold tanθ bold space bold plus bold space bold b to the power of bold 2 bold cotθ bold right parenthesis end fraction

bold equals bold space fraction numerator bold ab bold left parenthesis bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 bold right parenthesis over denominator bold 2 open parentheses bold a to the power of bold 2 bold tanθ bold space bold plus bold space bold b to the power of bold 2 bold cotθ close parentheses end fraction

 

A ને મહત્તમ થવા માટે, f(0) = a2tanθ + b2cotθ ન્યુનત્તમ થાય.

fraction numerator bold d bold left parenthesis bold f bold left parenthesis bold theta bold right parenthesis bold right parenthesis over denominator bold dθ end fraction= a2sec2-b2cosec2θ, f(θ) = 2b2cosec2a cotθ


fraction numerator bold d bold left parenthesis bold f bold left parenthesis bold theta bold right parenthesis bold right parenthesis over denominator bold dθ end fraction0 ⇒ tanθ = ± bold b over bold a

right enclose fraction numerator bold d bold left parenthesis bold f bold left parenthesis bold theta bold right parenthesis bold right parenthesis over denominator bold dθ end fraction end enclose bold space subscript bold tanθ bold space bold b over bold a bold space bold greater than bold space bold 0 end subscript

f(θ) એ tanθ = bold b over bold aહોય ત્યારે ન્યુનત્તમ થાય. અથી ન્યુનત્તમ f(θ) = bold a to the power of bold 2 bold space bold b over bold a bold space bold plus bold space bold b to the power of bold 2 bold space bold a over bold b bold space bold equals bold space bold 2 bold ab


bold therefore bold space bold A subscript bold max bold space bold equals bold space fraction numerator bold ab open parentheses bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 close parentheses over denominator bold 2 bold times bold 2 bold ab end fraction bold space bold equals bold space fraction numerator bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 over denominator bold 4 end fraction bold space

bold therefore bold space fraction numerator bold a to the power of bold 2 bold space bold minus bold space bold b to the power of bold 2 over denominator bold A subscript bold max end fraction bold equals bold space bold 4 bold space


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150.
વક્ર bold x bold space bold equals bold space bold a bold space square root of bold cos bold 2 bold theta end root bold space bold cosθ bold comma bold space bold y bold space bold equals bold space bold a square root of bold cos bold 2 bold theta end root bold space bold sinθ bold space bold ન ો bold space bold theta bold space bold equals bold pi over bold 6 bold space આગળનો સ્પર્શક ......... 
  • રેખા y = x ને સમાંતર છે.

  • રેખા x + y = 1 ને સમાંતર છે.

  • X-અક્ષને સમાંતર છે. 

  • Y-અક્ષને સમાંતર છે. 


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