Question

if TN=2n+3,find s3.with explaination plz it's very urgent ​

Answer 1

Answer:

Step-by-step explanation:

If T  

n

​  

=2n+3 then,

T  

1

​  

=(2×1)+3=2+3=5

T  

2

​  

=(2×2)+3=4+3=7

T  

3

​  

=(2×3)+3=6+3=9

Therefore, S  

3

​  

 is the sum of T  

1

​  

, T  

2

​  

 and T  

3

​  

 that is:

S  

3

​  

=T  

1

​  

+T  

2

​  

+T  

3

​  

=5+7+9=21

Hence, S  

3

​  

=21.