Question

Ciag : an= -n(kwadrat)+8
a) oblicz sume 3 i 5 wyrazu ciagu
b) wyznacz an-3

Answer 1

An=-n²+8
a1=-1+8    a1=7
a2=-4+8
a2=4     r=a2-a1
a3=-9+8
a3=-1
a5=-25+8
a5=-17
a3+a5=-1-17
a3+a5=-18



a(n-3)=-(n-3)²+8=-(n²-6n+9)+8=-n²+6n-9+8=-n²+6n-1

Answer 2