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jumlah-akar-akar-persamaan-x-2-2-x-3-0-sama-dengan-a-10-b-3-e-4-c-1-d-0-




Question Number 1039 by tera last updated on 22/May/15
jumlah akar−akar persamaan [x]^2 −2[x]−3=0 sama dengan  a.−10          b.−3      e.4  c.−1             d.0
jumlahakarakarpersamaan[x]22[x]3=0samadengana.10b.3e.4c.1d.0
Commented by prakash jain last updated on 22/May/15
[x] =⌊x⌋ =gint(x)?
[x]=x=gint(x)?
Commented by 123456 last updated on 22/May/15
y=[x]  y^2 −2y−3=0  Δ=(−2)^2 −4(1)(−3)=4+12=16  y=((−(−2)±(√(16)))/(2(1)))=((2±4)/2)=1±2  y_1 =1−2=−1  y_2 =1+2=+3  [x_1 ]=−1⇔−2≤x_1 ≤−1  [x_2 ]=+3⇔3≤x_2 ≤4
y=[x]y22y3=0Δ=(2)24(1)(3)=4+12=16y=(2)±162(1)=2±42=1±2y1=12=1y2=1+2=+3[x1]=12x11[x2]=+33x24
Commented by prakash jain last updated on 22/May/15
Please check.  ⌊−2⌋=−2  ⌊−1.5⌋=−2  ⌊x⌋=−1⇒−1≤x<0
Pleasecheck.2=21.5=2x=11x<0
Commented by 123456 last updated on 23/May/15
what if its is integer part?
whatifitsisintegerpart?
Answered by prakash jain last updated on 22/May/15
Taking [x] as floor function  y=⌊x⌋  y^2 −2y−3=0  (y+1)(y−3)=0  y=−1 or y=3  x∈[−1,0)∪[3,4)
Taking[x]asfloorfunctiony=xy22y3=0(y+1)(y3)=0y=1ory=3x[1,0)[3,4)

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