Ciąg arytmetyczny seyloreczek: Oblicz sumę, której składniki są kolejnymi wyrazami ciągu arytmetycznego. −5−7−9−...−29−31

Ajtek:

	a1+an
Sn=		*n
	2

a₁=... a₂=... a_n=... r=a₂−a₁ a_n=a₁+(n−1)*r

asdf: a1 = −5 a2 = −7 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− a2 − a1 = r −7 −(−5) = −2 r= −2 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− a_n = a1 + (n − 1)r a_n = −5 −2n + 2 a_n = −2n − 3 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −29 = −2n − 3 −26 = −2n −13 = −n n = 13 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

	(a1 + an)
Sn =		* n
	2

	−5 − 9
s3 =		* 3
	2

s₃ = −21 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

	−5 − 29
s13 =		* 13
	2

s₁3 = −221 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− s₁3 − s₃ = −221 + 21 = −200 s_x = −200 Sprawdź w odpowiedzi czy dobrze

asdf: s_x = SUMA CYFR UKRYTYCH (....) Źle przeczytałem

Aga1: a₁=−7, a₂=−7 r=a₂=a₁=−2 a_n=−31 n=14

	−5−31
S14=		*14=
	2

asdf: Aga1, literówka a₁ = −5

Aga1: Masz rację, ale wszystko liczone dla a₁=−5, i r=a₂−a₁=−2.

seyloreczek: Dziękuję Wam serdecznie!