Writing x = ar³, y = ar⁹ and z = ar¹⁵, we compute y² = (ar⁹)² = a²r¹⁸. Also x x z = (ar³) x (ar¹⁵) = a²r¹⁸. Since y² = x x z, x, y, z form a GP.
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The first term is 2 and the common ratio is 3. The explicit formula is tn equals 2 multiplied by 3 raised to n minus 1. Since 4374 equals 2 multiplied by 3 raised to 7, it is the eighth ...
The first term is 5 and the common ratio is 5. Using the GP formula, tn equals a multiplied by r raised to n minus 1. Therefore, tn equals 5 raised to n. The 10th term is 9765625.
Given a + 2d = 12 and a + 49d = 106, solving these simultaneous equations yields first term a = 8 and common difference d = 2. Therefore, the 29th term evaluates to 8 + 28 x 2 = ...
Here, first term is 21 and common difference is -3. Solving tn = a + (n – 1)d shows that -81 is the 35th term, and 0 is indeed the 8th term since n is a positive integer.