Find the first four terms of the sequence whose nth terms are given by (i) an = n3 −2

Find the first four terms of the sequence whose nth terms are given by

(i) an = n3 −2

Solution :

To find the 1st term, we have to apply n = 1

an = n3 −2 n = 1 a1 = 13 −2   =  1 -  2 a1  = -1	an = n3 −2 n = 2 a2 = 23 −2   =  8 -  2 a2  = 6
an = n3 −2 n = 3 a3 = 33 −2   =  27 -  2 a3  = 25	an = n3 −2 n = 4 a4 = 43 −2   =  64 -  2 a4  = 62

Hence the first four terms are -1, 6, 25, 62.