Question

Get the general term for the sequence being your t3 = 11 and the t20 = 244.2

Answer 1

Answer:

nth term = $t_{n} = 7.639(1.2)^{n - 1}$

Step-by-step explanation:

Let us assume that the given sequence is a G.P.

Now, if the first term of the G.P. is a and the common ratio is r, then

Third term = $t_{3} = ar^{2} = 11$ .......... (1) and  

20th term = $t_{20} = ar^{19} = 244.2$ ........... (2)

Now, dividing equation (2) with equation (1) we get

$\frac{ar^{19} }{ar^{2} } = \frac{244.2}{11} = 22.2$

⇒ $r^{17} = 22.2$

⇒ r = 1.2.

Hence, from equation (1) we get

a(1.2)² = 11

⇒ a = 7.639 (Approx.)

Therefore, the general term of the sequence i.e. nth term = $t_{n} = 7.639(1.2)^{n - 1}$ (Answer)