How many solutions does have in the interval ?
Answer and explanation
Correct answer: D.
- Step 1: Write (so ) and move everything to one side: .
- Step 2: Either , giving , or , giving .
- Step 3: None of these make , so all four are valid. There are solutions.
Answer
.
Why not the others: Dividing both sides by loses the solutions and , leaving only ; would arise by missing one of the two roots of ; and over-count.
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