Question

progresie geometrica a1=4 si r=-1 sa se calculeze suma primilor 10 termeni ai progresiei.

Answer 1

S₁₀=$\frac{a1(r^{10}-1) }{r-1} = \frac{4((-1)^{10}-1) }{-1-1}= \frac{4(1-1)}{-2}=0$