Câu hỏi 8

\(y = \sqrt 2 {\cos ^2}\left( {x + \frac{\pi }{4}} \right) + 1\)

Nhập: \(\left\{ \begin{array}{l}F\left( x \right) = \sqrt 2 {\cos ^2}\left( {x + \frac{\pi }{4}} \right) + 1\\Start = 0\\End = 2\pi \\Step = \frac{{End - Start}}{{19}} = \frac{{2\pi }}{{19}}\end{array} \right.\)

Nhìn cột \(F\left( x \right)\)thấy: \(\left\{ \begin{array}{l}Min\,f\left( x \right) \approx 1\left( { = 1,0216} \right)\\Max\,f\left( x \right) \approx 1 + \sqrt 2 \left( { = 2,4117} \right)\end{array} \right.\)

Chọn A.