Odpowiedź:
2.14
S = 2d(n- 2) = 2dn - 4d
S - 4d = 2dn
n = (S - 4d)/2d
2.15
I = (E/(R + r)
I * (R + r) = E
IR + Ir = E
Ir = E - IR
r = (E - IR)/I
2.16
S = (a + l)n/2
2S = (a + l)n
2S = an + ln
an = 2S - In
a = (2S - In)/n
