looks like an AS, with a = 13 , d = -2
tn + t(15-n)
= a + (n-1)d + a + (14-n)d
= a + nd - d + a + 14d - nd
= 2a + 13d
= 26 - 26
= 0
Consider the sequence 13;11;9;7;5...
A) show that Tn+T15-n=0
4 answers
How did 15 change into 14
a=13, d=-2
Tn+T15-n
a+(n-1)d + a+(15-n)d
a+dn-d + a+15d-dn
2a + 14d
2(13)+14(-2)
26-28= -2
* -2 < 15
Tn+T15-n
a+(n-1)d + a+(15-n)d
a+dn-d + a+15d-dn
2a + 14d
2(13)+14(-2)
26-28= -2
* -2 < 15
How did 15 change to 14