Question

If the n th term is (2n-3).Find the fifthteen term

Answer 1

You must be in Egypt i have the same exact type of questions, this is an arithmetic or geometric sequence i assume, let's find out

So what you're gonna do is place n by the numbers from 1

if n=1
2n - 3
2(1) - 3
= -1

If n= 2
2(2) - 3
= 1

If n=3
2(3) -3
= 3

Now to know if it's arithmetic sequence we do (one term minus the one before it) so 3-1 = 2 and 1 - (-1) = 2 , this means that it's an arithmetic sequence
To know the fifteenth term we apply the rule of the general term which is : Tn = a+(n-1) d

So to do that we have to know ( a ) which is the first term of the sequence (T1) which we already know is ( -1 ) and ( d ) which is the difference which we already know is ( 2 )
Now all we have to do is place the numbers instead of the letters

Tn= a + (n-1) d
T15 = (-1) + (15-1) (2)
= 27
So the fifteenth term (T15) equals 27

Btw i love the arithmetic and geometric sequence Love solving them so i had fun answering this, i hope it helped you so sorry it's long