Question

 

Answer 1

Do \(sinx\le1\) nên \(y\le3.1+\dfrac{1}{2}=\dfrac{7}{2}\)

Dấu "=" xảy ra \(\Leftrightarrow\sin x=1\Leftrightarrow x=90^0\)

Vậy \(y_{max}=\dfrac{7}{2}\)

Answer 2

`y=3` `sin` `x+1/2`

Vì `-1` `<=` `sin` `x` `<=` `+` `1/2`

`=>-3` `<=` `3` `sin` `x` `=` `3`

`=>-5/2` `<=` `3` `sin` `x` `+` `1/2` `<=` `7/2`

`=>-5/2` `<=` `y` `<=` `7/2`

Vậy `max` `y` `=7/2`

Chọn `A`