բ)3! 1*2*3=6
դ)n! =1*2*3…n
p=1/6=3!1*2*3=6
բ)2/6=1/3
դ)0/6=0
բ)p6=6!=1*2*3*4*5*6=720
Մխիթար Սեբաստացի Ավագ դպրոց 9- րդ դասարան
բ)3! 1*2*3=6
դ)n! =1*2*3…n
p=1/6=3!1*2*3=6
բ)2/6=1/3
դ)0/6=0
բ)p6=6!=1*2*3*4*5*6=720
ա)
a2-a1=5
a3-a2=5
a4-a3=10
a5-a4=5
բ)
Թվաբանակայն պրոգրեսիա չէ
ա)
d=6
բ)
a7=a1+6d=37
a8=a1+7d=44
a9=a1+8d=49
a10=a1+9d=55
ա)
d=a4-a3=4
a2=a3-d=1
բ)
d=a4-a3=4
a2=a2-d=3
գ)
d=-2
a5=a4+a6/2=10
դ)
a7=a6+a8/2=-13
d=a8-a7=2
ա)
a2=a1+a3/2=9
d=a2-a1=9-5=4
բ)
a10=a2+8d
16=8d
d=2
a1=a3-a2=5-3=2
գ)
a12=a3+9d
-9=9d
d=-1
a2=7-(-1)=8
դ)
a12=a7+5d
10=5d
d=2
a101=101*2=202
ա)
a17=a17+a19/2=6
բ)
a20=a19+a21/2=-10
գ)
a5=a3+a7/2=3
դ)
a8=a2+a14/2=14
ա)
x1=2
x2=4
x3=6
x4=8
x5=10
x6=12
բ)
xn=2n
x7=14
x8=16
x20=40
ա) xn=n
բ) xn=2n-1
գ) xn=4n
դ) xn= 1/n
ե) xn= -1n+1
զ) xn=-1n-1
ա)
a1=2
a2=4
a5=14
a100=299
բ)
a1=0
a2=5
a12=24
a30=61
ա)
a1=3+2
a2=3 * 2 + 2 = 6 + 2 = 8
a3=3 * 3 + 2 = 9 + 2 = 11
a10=3 * 10 + 2 = 30 + 2 = 32
ա)
a2 = a1 + 3 = 5
a3 = a2 + 3 =8
a4 = a3 + 3 =11
a5 = a4 + 3 = 14
գ)
c2 = c1 – 8 =-4
c3 = c2 – 8 =-12
c4 = c3 –-20
c5 = c4 – 8 =28
ա)
⌈x+y-7=0 ⌈y=7-x ⌈y=7-x
⌊x2+xy+y2=43 ⌊x2+x(7-x)+(7-x)2=43 ⌊x2+7x-x+49-14x+x2=43
⌈y=7-x ⌈y=7-3=4
⌊2x^2-8x+6=0 ⌊x=3
բ)
⌈x+y-6=0 ⌈x=6-y ⌈x=6-y
⌊2x^2-y^2=-23 ⌊2(6-y)^2-y^2=-23 ⌊72-24y+2y^2-y^2=-23
⌈x=6-y ⌈x=6-5=1
⌊95-24y+y^2 ⌊y=5
գ)
⌈x+y=3 ⌈x=3-y ⌈x=3-y
⌊x^2-y^-4xy+11=0 ⌊(3-y)^2-y^-4(3-y)y+11=0 ⌊9-6y-12y+4y^2+11=0
⌈x=3-y ⌈
⌊2+18y+4y^2=0 ⌊1+9y+2y^2=0
ա)
{x+y=2 {x=2-y {x=2-y
{9x^2-3xy+y=1 {9(2-y)^2-3(2-y)y+y=1 {36-36y+9y^2-6y+3y^2+y=1
{x=2-y
{35-41y+12y^2=0
ա) x(x2+5x+6)=0
x2+5x+6=0
D=25-4·6·1=1
x1=-b2-√D/2a=-5-1/2=-3
x2=-b2+√D/2a=-5+1/2=-
x=0
գ) -x4-2x³-3x²=0
x²(x²-2x+3)=0
x²=0 x²-2x+3=0
x=0 D=16
x1=-3
x2=1
ա) 3x+3=0 2x+5=0
3x=-3 2x=-5
x=-1 x=-5/2
գ) 5-x=0 3x+2=0
-x=-5 3x=-2
x=5 x=-2/3
ա) x-2≠0 x2+2x=0
x≠2 x(x+2)=0 => x=0; x=-2
Առաջադրանք 67․
բ․ y = x2 – 7x – 8
x0= — b/2a = -7/2 = 7/2
y0= — D/4a = -b2 – 4ac/4a = 81/4 = 20,25
Համաչափության առանցք՝ x = 7/2
դ․ y = 5x2+ 4x – 2
x0= -b/2a = -2/5 = -0,4
y0= -D/4a = -b2 – 4ac/4a = 8/5 = 1,6
Համաչափության առանցք՝ x = -0,4։
Առաջադրանք 68․
բ․ y = x2+ 2x – 3
x0= -b/2a = -1
y0= -D/4a = -b2 – 4ac/4a = 12
դ․ y = 9x2 – 12x + 3
x0= -b/2a = -12/9 = 12/9 = 2/3
y0= -D/4a = -b2 -4ac/4a = 36/36 = 1։
Առաջադրնանք 69․
բ․ y = – x2+ 9
x0= -b/2a = 9/2 = 4 1/2 = 4,5
y0= -D/4a = -b2 -4ac/4a = 5/4 = 1 1/4 = 1,25
դ․ y = 1/9x2+ 2/3x + 5
x0= -b/2a = -3
y0= -D/4a = -b2 -4ac/4a = 4։