If , then is equal to :

Question

If , then  is equal to :

Canvas Classes · Accepted Answer

🧠 Read the Condition Again — It Hides a Beautiful Identity

Read the given condition slowly: . Rewrite it as . That single line is the key to the whole question.

So we have . Now look at :

.

So  and  are the same number. Let me call this common value . Then  for every . Every pair  in that long sum is just .

Once you spot this, the giant expression collapses into a small polynomial in . That is the move the examiner wants.

🗺️ Working It Out

With , the expression becomes

.

Now I need th

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