Question

The explicit formula for a sequence is

an=−2+3/2(n−1)
What is the 21st term of the sequence?

Answer 1

Explanation:

From the given question it appears that (n-1) is in the numerator's place, if it is so, then let us solve it.

`a_n = - 2 + (3)/(2)(n - 1) \\ \\ \therefore \: a_(21) = - 2 + (3)/(2) (21 - 1) \\ \\ \therefore \: a_(21) = - 2 + (3)/(2 ) * \: 20\\ \\ \therefore \: a_(21) = - 2 + 3 * \: 10 \\ \\ \therefore \: a_(21) = { -2 + 30} \\ \\ \therefore \: a_(21) = 28 \\ \\ \huge \red{ \boxed{\therefore \: a_(21) = 28} } \\ \\`