[tex]a_1=-\frac{3}{2}[/tex]
[tex]a_2=3[/tex]
[tex]q=3:(-\frac{3}{2})=3*(-\frac{2}{3})=-2[/tex]
[tex]S_{11}=-\frac{3}{2}*\frac{1-(-2)^{11}}{1+2}[/tex]
[tex]S_{11}=-\frac{3}{2}*\frac{1-(-2048)}{3}[/tex]
[tex]S_{11}=-\frac{3*2049}{2*3}[/tex]
[tex]S_{11}=-\frac{2049}{2}[/tex]
[tex]S_{11}=-1024\frac{1}{2}=-1024,5[/tex]
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Greetings from Poland :)
