Finding nth arithmetic mean between a and b

If  A1 , A2 , A3 ,............, Aare nth arithmetic means inserted  between a and b.

Then   a , A1 , A2 , A3 ,............, A, b   are in A P

here first term = a

 Common   difference   is given by      \[d=\frac{(b-a)}{n+1} \] 

then b =  a + (n + 2 - 1) d 

           =a+(n+1)*d

\[A_{1}=a+\frac{b-a}{n+1} \]

\[A_{2}=a+\frac{2(b-a)}{n+1} \]

\[A_{3}=a+\frac{3(b-a)}{n+1} \]

......

.....

......

\[A_{n}=a+\frac{n(b-a)}{n+1} \]

For example 

Insert  5 Arithmetic mean between 1 and 11 

Then AP what we get can be written as 1 , A1 , A2 , A3 , 4,  A5, 11

here total no of terms = 5+2 =7

   \[d=\frac{(b-a)}{n+1} \]   where n is no of arithmetic mean inserted

   \[d=\frac{11-1}{5+1}=\frac{10}{6} \]

\[A_{1}=1+\frac{10}{6}=\frac{16}{6} \]

\[A_{2}=1+\frac{20}{6}=\frac{26}{6} \] 

\[A_{3}=1+\frac{30}{6}=\frac{36}{6}=6 \]

\[A_{4}=1+\frac{40}{6}=\frac{46}{6} \] 

\[A_{5}=1+\frac{50}{6}=\frac{56}{6} \]

  

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