No. You didn't even wait ten minutes. Did you think about it? Look, if you expect to do well in Math, you can't expect that you will always have someone over your shoulder telling you what to do next. I am not going to write this in "induction form", but I will reiterate what I said before:
1)Prove that for any integer k, 1+2+...+k = k(k+1)/2. You have said that you can do inductive proofs, this is a rather basic inductive proof, in fact, it is the most basic inductive proof I can think of. If you can do induction, you can do this. And I am not going to tell you how to use induction, you are going to have to figure that out own your own. Spend a little time, put some effort into it.
2)So now that you know that 1+2+...+k=k(k+1)/2 what can you conclude? This part involves NO INDUCTION AT ALL. Think about these things: Is k even or odd? Is k+1 even or odd? Is k/2 an integer? Is (k+1)/2 an integer? How do the answers to these questions relate to what I am trying to prove?
Now, spend some time on this. You are giving up way too easily. Like I said, if you want to be successful at math, whether you are doing research, working in some applied area or teaching, you are going to have to figure stuff out for yourself. We have given you ample "hints" (we have, in fact, done much more than that), if you refuse to think about it, there really isn't a lot more that we can do.