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ગણિતિય અનુમાનો સિદ્વાંત

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JEE ગણિત પ્રશ્ન બેંક ભાગ 1

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ગણિત

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Class 10 Class 12
વિધાન p(n) : 32n+1+2n-1 એ  n ∈ N .......... ના ગુણકમાં છે.
  • 4

  • 7

  • 5

  • 2


bold p bold left parenthesis bold n bold right parenthesis bold space bold colon bold space bold 2 to the power of bold 2 to the power of bold 2 end exponent નો એકમનો અંક ....... છે. n > 1 
  • 0

  • 4

  • 6

  • 2


વિધાન bold p bold left parenthesis bold n bold right parenthesis bold space bold colon bold space bold n to the power of bold 3 over bold 3 to the power of bold n bold space bold less than bold space bold n bold factorial bold space bold less than bold space bold n to the power of bold n over bold 2 to the power of bold n દરેક n ≥ k, n ∈ N માટે સત્ય છે, તો k = .......... .  
  • 6

  • 5

  • 4

  • 3


વિધાન p(n) : n≥ 3n ........ સત્ય છે. 
  • n ∈ N
  •  n ∈ N, n > 1
  •  n ∈ N, n ≥ 3
  • દરેક અયુગ્મ પ્રાકૃતિક સંખ્યા

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જો bold a subscript bold n bold space bold equals bold space square root of bold 7 bold plus square root of bold 7 bold plus square root of bold 7 bold plus bold. bold. bold. end root end root bold space bold n વખત તો ગણિતીય અનુમાનના સિદ્વાંત પરથી કયું સત્ય છે?
  • an > 7,  n ≥ 1
  • an > 3,  n ≥ 1
  • an < 4,  n ≥ 1
  • an < 3,  n ≥ 1

C.

an < 4,  n ≥ 1

Tips: -

bold p bold left parenthesis bold n bold right parenthesis bold space bold colon bold space bold a subscript bold n bold space bold equals bold space square root of bold 7 bold plus square root of bold 7 square root of bold 7 bold plus bold. bold. bold. end root end root end root bold space bold n વખત
 
n = 1લેતાં, a1square root of bold 7 આથી a1 < 7 હોવાથી an > 7 સત્ય નથી.
 
a1 > 3 સત્ય નથી. a1square root of bold 7 bold space bold greater than bold space bold 4 અને a1square root of bold 7 < 3 સત્ય છે. 

bold a subscript bold 2 bold space bold equals bold space square root of bold 7 bold plus square root of bold 7 end root
અહીં bold 2 bold space bold less than bold space square root of bold 7 bold space bold less than bold space bold 3 bold space bold rightwards double arrow bold space bold 9 bold space bold less than bold space bold 7 bold space bold plus bold space square root of bold 7 bold space bold less than bold space bold 10 bold space bold less than bold space bold 10 bold space bold rightwards double arrow bold space bold 3 bold space bold less than bold space square root of bold 7 square root of bold 7 end root bold space bold less than bold space bold 4 bold space bold rightwards double arrow bold space bold 3 bold space bold less than bold space bold a subscript bold 2 bold space bold less than bold space bold 4

∴ a2 < 3 સત્ય નથી. પરંતુ a2 < 4 સત્ય છે. 

આમ, a1 < 4, a2 < 4 સત્ય છે. 

ધારો કે ak < 4 

હવે, ak+1square root of bold 7 bold plus square root of bold 7 bold plus square root of bold 7 bold plus bold. bold. bold. end root end root end root bold space bold k bold space bold plus bold space bold 1 વખત 

              bold equals bold space square root of bold 7 bold plus bold a subscript bold k end root

bold therefore bold space bold a to the power of bold 2 subscript bold k bold plus bold 1 end subscript bold space bold equals bold space bold 7 bold space bold plus bold space bold a subscript bold k bold space bold less than bold space bold 7 bold space bold plus bold space bold 4 bold. આથી bold a subscript bold k bold plus bold 1 end subscript bold space bold less than bold space square root of bold 11 bold space bold less than bold space bold 4 આથી bold a subscript bold k bold plus bold 1 end subscript bold space bold less than bold space bold 4 

આમ, an <4, n = k+1 માટે સત્ય છે.

bold therefore bold space bold a subscript bold n bold space bold less than bold space bold 4 bold comma bold space  n ∈ N

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