Find the slope of the tangent to the curve

Find the slope of the tangent to the curve

i. $y=\left(x^{3}-x\right)$ at $x=2$

ii. $y=\left(2 x^{2}+3 \sin x\right)$ at $x=0$

iii. $\mathrm{y}=(\sin 2 \mathrm{x}+\cot \mathrm{x}+2)^{2}$ at $\mathrm{x}=\frac{\pi}{2}$