જો ; a,b,c ∈ R, abc = 1, AAT = 64 I અને |A| > તો (a3 + B3 + C3)3 from Mathematics શ્રેણિક

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Gujarati JEE Mathematics : શ્રેણિક

Multiple Choice Questions

41. જો bold A bold space bold equals bold space open square brackets table row cell bold minus bold 1 end cell cell bold minus bold 2 end cell cell bold minus bold 2 end cell row bold 2 bold 1 cell bold minus bold 2 end cell row bold 2 cell bold minus bold 2 end cell bold 1 end table close square brackets તો adj A = ....... 
  • 3AT

  • 3A

  • AT

  • A


42. bold જ ો bold space bold A bold space bold equals bold space bold left square bracket bold 2 bold space bold minus bold space bold 3 bold space bold 4 bold right square bracket bold comma bold space bold B bold space bold equals bold space open square brackets table row bold 3 row bold 2 row bold 1 end table close square brackets bold comma bold space bold X bold space bold equals bold space bold left square bracket bold 0 bold space bold 2 bold space bold 3 bold right square bracket bold space bold અન ે bold space bold Y bold space bold equals bold space open square brackets table row bold 2 row bold 2 row bold 4 end table close square brackets bold space bold ત ો bold space bold AB bold space bold plus bold space bold XY bold space bold equals bold space bold. bold. bold. bold. bold. bold. bold. bold space
  • 20

  • -20

  • [-20]

  • [20]


43.
જો સમીકરણ λx + 2y - 2z = I, 4x + 2λy - z = 2 અને 6x + 6y + λz = 3, નો અનન્ય ઉકેલ મળે તો, 
  • λ#1

  • λ#2

  • λ#3

  • λ#-2


44. bold A bold space bold equals bold space open square brackets table row bold 1 bold 3 row bold 3 bold 4 end table close square brackets bold space bold અન ે bold space bold A to the power of bold 2 bold space bold minus bold space bold 5 bold A bold space bold equals bold space bold kI bold space bold ત ો bold space bold space bold k bold space bold equals bold space bold. bold. bold. bold. bold. bold. bold. bold space
  • 5

  • 6

  • 7

  • 8


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45. bold જ ો bold space bold A bold space bold equals bold space open square brackets table row bold 1 bold cotθ row bold cotθ bold 1 end table close square brackets bold space bold મ ા ટ ે bold space bold left parenthesis bold A to the power of bold minus bold 1 end exponent bold right parenthesis to the power of bold 2 bold space bold F bold left parenthesis bold theta bold right parenthesis bold space open square brackets table row cell bold minus bold cos bold 2 bold theta end cell cell bold minus bold sin bold 2 bold theta end cell row cell bold sin bold 2 bold theta end cell cell bold minus bold cos bold 2 bold theta end cell end table close square brackets bold space bold ત ો bold space bold f bold left parenthesis bold theta bold right parenthesis bold space bold equals bold space bold. bold. bold. bold. bold. bold. bold. bold space
  • cos2θ

  • cos θ

  • sin θ

  • sin2θ


46. જો A = diag [3 2 1], તો ઍ-1 ના ઘટકોનો સરવાળો ......... છે. 
  • bold 1 over bold 6
  • bold 5 over bold 6
  • bold 11 over bold 6
  • 6


47. bold જ ો bold space bold A bold space bold equals bold space open square brackets table row bold 1 bold 1 row bold 0 bold 1 end table close square brackets bold comma bold space bold B bold space bold equals bold space bold. bold. bold. bold. bold. bold. bold. bold. bold space bold જ ે થ ી bold space bold space bold AB bold space bold equals bold space bold BA bold. bold space bold જ ્ ય ાં bold space bold B bold space bold # bold space bold 1 bold space
  • open square brackets table row bold x bold x row bold 1 bold x end table close square brackets
  • open square brackets table row bold x bold y row bold 0 bold y end table close square brackets
  • open square brackets table row bold x bold y row bold 0 bold x end table close square brackets
  • open square brackets table row bold x bold x row bold y bold 0 end table close square brackets

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48. જોbold A bold space bold equals bold space open square brackets table row cell bold 3 bold a end cell bold b bold c row bold b cell bold 3 bold c end cell bold a row bold c bold a cell bold 3 bold b end cell end table close square brackets ; a,b,c ∈ R, abc = 1, AAT = 64 I અને |A| > તો (a3 + B3 + C3)3
  • 256

  • 343

  • 512

  • 729


B.

343

Tips: -

અહીં AT = A થાય.

A2 = 64 I


|A|2 = 64 ⇒|A| = 8

bold vertical line bold A bold vertical line bold space bold equals bold space open vertical bar table row cell bold 3 bold a end cell bold b bold c row bold b cell bold 3 bold c end cell bold a row bold c bold a cell bold 3 bold b end cell end table close vertical bar

= 3a[9bc - a2] - b[3b2 - ca] + c[ab - 3c2]

|A| = 8 ⇒ 29abc - 3 (a3 + b3 + c3) = 8


a3 + b3 + c3 = 7


(a3 + b3 + c3)3 - 343


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49. bold જ ો bold space bold 2 bold space bold X bold space bold plus bold space open square brackets table row bold 1 bold 2 row bold 3 bold 4 end table close square brackets bold space bold equals bold space open square brackets table row bold 3 bold 8 row bold 7 bold 2 end table close square brackets bold space bold ત ો bold space bold X bold space bold equals bold space bold. bold. bold. bold. bold. bold. bold. bold space
  • open square brackets table row bold 1 bold 3 row bold 2 cell bold minus bold 1 end cell end table close square brackets
  • open square brackets table row bold 1 cell bold minus bold 3 end cell row bold 2 cell bold minus bold 1 end cell end table close square brackets
  • bold 2 open square brackets table row bold 1 bold 3 row bold 2 cell bold minus bold 1 end cell end table close square brackets
  • bold 2 bold space open square brackets table row bold 1 cell bold minus bold 3 end cell row bold 2 cell bold minus bold 1 end cell end table close square brackets

50. જો ચોરસ શ્રેણિક A અને B માટે AB અને BA = B તો B2 = ...... 
  • 0

  • A

  • B

  • I


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