Consider the following statements

$\mathrm{I}.$ $\sin 66°$ is greater than $\cos 66°$

$\mathrm{II}.$ $\cos 26°$ is smaller than $\sin 26°.$

Which of the above statement$\left(s\right)$ is$/$are correct$?$

If $A, B, C, D$ are the angles of a cyclic quadrilateral taken in order, then consider the following statements

$\mathrm{I}.$ $\cos A+\cos B=-(\cos C+\cos D)$

$\mathrm{II}.$ $\cos (\pi +A)+\cos (\pi -B)+\cos (\pi -C)$$-\sin \left(\frac{\pi }{2}-D\right)=0$

Which of the above statement(s) is / are correct$?$