Question 915764
<pre>

{{{a[2]-a[1]=9/4-3/2=9/4-6/4=3/4}}}
{{{a[3]-a[2]=3-9/4=12/4-6/4=3/4}}}

So it's an arithmetic sequence with {{{d=3/4}}} and {{{a[1]=3/2}}} 

{{{a[n]=a[1]+(n-1)d}}}

{{{a[n]=3/2+(n-1)*expr(3/4)}}}

Clear of fractions by multiplying through by 4

{{{4a[n]=6+(n-1)3}}}

{{{4a[n]=6+3(n-1)}}}

{{{4a[n]=6+3n-3=3+3n=3(1+n)}}}

Solve for a<sub>n</sub>

{{{a[n]=3(1+n)/4}}}

Edwin</pre>