Question

Sa se scrie primii patru terme i ai progresiei aritmetice a1=2/7; a2=1/5

Answer 1

$a_{1} = \frac{2}{7}$

$a_{2} = \frac{1}{5}$

$r = a_{2} - a_{1}$

$r = \frac{1}{5} - \frac{2}{7}$

$r = \frac{7}{35} - \frac{10}{35}$

$r = \frac{7 - 10}{35}$

$r = - \frac{3}{35}$

$a_{3} = a_{2} + r$

$a_{3} = \frac{1}{5} - \frac{3}{35}$

$a_{3} = \frac{7}{35} - \frac{3}{35}$

$a_{3} = \frac{7 - 3}{35}$

$a_{3} = \frac{4}{35}$

$a_{4} = a_{3} + r$

$a_{4} = \frac{4}{35} - \frac{3}{35}$

$a_{4} = \frac{4 - 3}{35}$

$a_{4} = \frac{1}{35}$

Answer 2

Ratia este a2-a1. Adica: 1/5 - 2/7 => ratia este -3/35

Termenul 3= a2+r = 1/5-3/35=4/35

Termenul 4 = a3+r = 4/35-3/35=1/35