Giá trị nhỏ nhất của hàm số $y = 2x + \cos x$ trên đoạn $\left[ {0;1} \right]$ là :

$- \dfrac{1}{2}; - \dfrac{{\sqrt 3 }}{2}$

$- \dfrac{{\sqrt 3 }}{2}; - 1$

$- \dfrac{{\sqrt 3 }}{2}; - 2$

$- \dfrac{{\sqrt 2 }}{2}; - \dfrac{{\sqrt 3 }}{2}$

$f\left( x \right) \geqslant  - 2,\forall x \in \left[ {1;3} \right]$ 

$f\left( 1 \right) = f\left( 3 \right) =  - 2$

$f\left( x \right) <  - 2,\forall x \in \left[ {1;3} \right]$                     

$f\left( x \right) \leqslant  - 2,\forall x \in \left[ {1;3} \right]$

$f\left( 0 \right) < 5$

$f\left( 2 \right) \geqslant 5$ 

$f\left( 1 \right) = 5$      

$f\left( 0 \right) = 5$

$\mathop {\min }\limits_{\left[ { - 3;\,\,1} \right]} g\left( x \right) = g\left( { - 1} \right)$.

$\mathop {\min }\limits_{\left[ { - 3;\,\,1} \right]} g\left( x \right) = g\left( 1 \right)$

$\mathop {\min }\limits_{\left[ { - 3;\,\,1} \right]} g\left( x \right) = g\left( { - 3} \right)$

$\mathop {\min }\limits_{\left[ { - 3;\,\,1} \right]} g\left( x \right) = \dfrac{{g\left( { - 3} \right) + g\left( 1 \right)}}{2}$

$- 16$.

$4$.

$\dfrac{{ - 1}}{{16}}$.

$\dfrac{1}{4}$.

$m = 2$

$m = 5$

$m = 3$

$m = 4$