Question

What is the twenty-first term of the sequence given by xn = 4n − 3 ?

Answer 1

Answer:

Step-by-step explanation:

an= 3+{ -1}*n

a1 = 3+{-1}*1=2

a2= 3 +{-1}*2= 4

a3=3+{-1}*3=2

a4=3+[-1}*4=4

Answer 2

The twenty-first term of the sequence is 81.

Given:

$x_{n}$ = 4n − 3

To Find:

The twenty-first term of the sequence given by $x_{n}$ = 4n − 3.

Solution:

The general term of any sequence is represented by its $n^{th}$ term.

Here the $n^{th}$ term of a sequence is given to be $x_{n}$ = 4n − 3.

So the twenty-first term can be found out by replacing n with 21 in the given formula.

⇒ $x_{21}$ = 4 x (21) - 3 = 84 - 3

⇒ $x_{21}$ = 81.

Hence, the twenty-first term of the sequence is 81.

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