how to prove the induction problem

**yingao** · April 1st 2012, 01:36 PM

4+8+12+...+4n= 2n(n+1)

**Plato** · April 1st 2012, 01:50 PM

Originally Posted by yingao

4+8+12+...+4n= 2n(n+1)

Can you show that it is true for $n=1~?$

**yingao** · April 1st 2012, 03:50 PM

4n= 2n(n+1)

4 x1 = 2x1 (1+1)

4 = 4

**Plato** · April 1st 2012, 03:54 PM

Originally Posted by yingao

4n= 2n(n+1)
4 x1 = 2x1 (1+1)
4 = 4

O.K.
Now if we know that for K>1, 4+8+12+...+4K= 2K(K+1) what can say about 4+8+12+...+4K+4(K+1)?

**yingao** · April 1st 2012, 04:20 PM

Thanks for your help! I don't know how to go on from here.

Thread: how to prove the induction problem