Question 22: Given the function \(y = – {x^4} + 2{x^2} + 3\). Which of the following statements is correct?

Yes \(y’ = – 4{x^3} + 4x\)

\(y’ = 0 \Leftrightarrow \left[\begin{array}{l}x=0\\x=1\\x=–1\end{array}\right\)[\begin{array}{l}x=0\x=1\x=–1\end{array}\right\)

Since the function is a quadratic function with coefficient a < 0 and the equation y' = 0 has 3 distinct solutions, the function has 2 maxima and 1 minimum.

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