Prove the identity: simplifies to:
Answer and explanation
Correct answer: C.
- Step 1: Expand: .
- Step 2: and , so constant is .
- Step 3: , bringing sum to .
- Step 4: and .
- Step 5: Total: .
Answer
.
Why not the others: forgets the terms from and expansions; adds 2 extra units; and option with is not fully simplified.
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