Question

for a sequence if Sn =2(3^n-1) ,show that the sequence is a G.P and hence find t3​

Answer 1

Answer:

A white gelatinous precipitate is formed which is soluble in excess of sodium hydroxide.

Answer 2

Answer:

S  

n

​  

=4n  

2

−3n

Now, S  

n+1

​  

=4(n+1)  

2

−3(n+1)

We know that, t  

n+1

​  

=S  

s+1

​  

−S  

n

​  

 

t  

n+1

​  

=4n  

2

+5n+1−4n  

2

+3n

t  

n+1

​  

=8n+1

Thus t  

n+1

​  

 is linear equation of n  

hence it is an A.P

Now t  

n+1

​  

=8n+1

comlplaning with a  

n+1

​  

=a+(n−1)  

a=1   and   d=8