oblicz perwszy wyraz ciagu geometrycznego an jeśli A) a4=1, q=1/2 B) a6= 16, q= -2 C) a8=81, q=3

a) a₄=a₁·q³ 1=a₁·[latex] frac{1}{2} [/latex]³ 1=a₁·[latex] frac{1}{8} [/latex] /·8 8=a₁ b) a₆=a₁·q⁵ 16=a₁·(-2)⁵ 16=a₁·(-32) //(-32) a₁= - [latex] frac{16}{32} [/latex] = - [latex] frac{1}{2} [/latex] c)a₈=a₁·q⁷ 81=a₁·3⁷ 2187a₁=81 //2187 a₁=[latex] frac{81}{2187} [/latex]=[latex] frac{1}{27} [/latex]