ocr: The sequence is 4,12,36,108,324,. - : To use the formula an = a1 +rn-1, n>1, - you need a1 which is 4; n, which will be given; and r. - r-an - 12 - - - = - an-1 4 Term number an == airn-1 Term 6 ae =4.36-1 972 7 a7 =4.37-1 2,916 10 210 =4.310-1 78,732 15 215 - =4.315-1 19,131,876 25 225 =4.325-1 1.13x1012 Arithmetic and Geometric Sequences
