Progresii aritmetice - exercitiu rezolvat 6

Stiind termenii progresiei aritmetice:

 C₃ = 7 si C₅ = 13

Sa se afle termenii C₉, C₂ si C₁₅

Stiind ca C₃ = 7 =>           C₁ + 2r = 7   /*(-1)

Stiind ca C₅ = 13 =>         C₁ + 4r = 13

                                         - C₁ – 2r = -7

                                            C₁ + 4r = 13

                                            /       2r = 6

                                                      r = 3

C₁+ 6 = 7 => C₁ = 7 – 6 => C₁ = 1

C₉ = C₁ + 8r => 1 + 8 * 3 => 1 + 24 = C₉ = 25

C₂ = C₁ + r => 1 + 3 => C₂ = 4

C₁₅ = C₁ + 14r => 1 + 14 * 3 => 1 + 42 => C₁₅ = 43



Formule progresii aritmetice

Exercitii si probleme rezolvate clasa a-X-a

Probleme si exercitii rezolvate