Zadania w załączniku ,,CIĄGI' bardzo pilne!! DAM NAJ !

[latex]Zad 1 \a_1=2\r=5-1=3\Zad 2\x= frac{138+84}{2}= 111\Zad 3\egin{cases} a_2=a_1+r=5\a_3=a_1+2r=7end{cases}\2r-r=7-5=r=2\Zad 4\a_1=3\r=2\S_{20}= frac{2a_1+19r}{2}20=10(6+38)=420\[/latex] [latex]Zad 5\a_1=3\r=2\S_n= frac{2a_1+7r}{2}8=4(6+14)=80\ Zad 6\a_3=aq^2=9\a_5=aq^4=81 \ frac{a_5}{a_3}=q^2\q_1=3 q_2=-3\a_1=1\a_n=q^{n-1}\Zad 7\a_1=2\q=3\Sn=a_1 frac{1-q^n}{1-q} =2 frac{1-3^{10}}{-2}=3^{10}-1= 59048\[/latex] [latex]Zad 8\ q=2\a_1=5\Sn=a_1frac{1-q^6}{1-q}=5* frac{63}{1}=315\Zad 9\5000*1,16*1,16=6728 zl\Zad 10\3000*(1,015)^4=3184 zl[/latex]