Question

Proszę o rozwiazanie zadań z ciągów
zadania w zalaczniku

Answer 1

5]
n²+2n-24<0
Δ=4+96=100
n1=[-2-10]/2=-6
n2=[-2+10]/2=4
n∈(-6,4)
ujemne sa wyrazy ; a1,a2,a3
6]
a2=2-9*2²=2-36=-34
a5=2-9*5²=2-225=-223
a(n+1)=2-9(n+1)²=2-9n²-18n-9=-9n²-18n-7
7]
a9-a2=[ 3 /(9²-1)]  - [ 3/(2²-1)]=3/80-1=3/80-80/80=-77/80
8]
a]
4x-9=[6+16]/2
8x-18=22
8x=22+18
x=40/8
x=5
////////////
a2=4*5-9=11
b]
x+4=√[2/3*8/3]
x+4=√16/9
x+4=4/3
x=4/3-12/3
x=-8/3
a2=x+4=-8/3+12/3=4/3
9]
a]
2x+4=[x-1+x+7]/2
4x+8=2x+6
2x=-2
x=-1
a1=-1-1=-2
a2=2*(-1)+4=2
a3=-1+7=6
b]
[3x+12]²=[x-1][x-10]
9x²+72x+144=x²-10x-x+10
8x²+83x+134=0
Δ=6889-4288=2601                √Δ=51
x1=[-83-51]/16=-134/16=-67/8

czyli;
a1=x-1=-67/8-8/8=-75/8
a2=3x+12=-201/8+96/8=-105/8
a3=x-10=-75/8-80/8=-155/8
-155/8: (-105/8) ?= -105/8;(-75/8)
155/8*8/105?=105/8*8/75
31/21?=21/15  NIE , czyli sprzeczne
odp.
x=x2
x2=[-83+51]/16=-2
dla x=-2:
a1=-3-1=-3
a2=-6+12=6
a3=-2-10=-12
10a]
r=26-18=8
a3=18-8=10
a2=10-8=2
a1=2-8=-6
b]
q=1/27*3=1/9
a3=1/3*9=3
a2=3*9=27
a1=27*9=243