The value of ∑45n=1in+in+1 is ____________
Hint: ∑tn+tm = ∑tn+∑tm
i
0
i+1
i-1
∑45n=1in+in+1 = ∑45n=1in+∑45n=1in+1
= (i+i2+i3+.................+i45)+(i2+i3+...................+i46)
= i45+i46 = i+i2 = i−1
(a) Tn = n find (i) Tn+1 (ii) T n−1
(b) If Tn = n2 − 1 find (i) Tn−2 (ii) Tn+1
(c) If Tn = 2n2 + 1 find the value of n if Tn = 73
(d) In a sequence Tn = 5 − 3n find (i) Tn+1 (ii) Tn+2