1. Show that the upper half of the equation of the circle centered at $(0,0)$ and of radius $1$ may be given by the function

   $$f(x)=\sqrt{1-x^2},-1\le x\le 1$$

2. By applying the trapezium rule with $6$ strips to

   $${\int }_0^{1}f(x)dx$$

   find an approximate value for $\pi .$

Give the approximation obtained, to $3$ significant figures.