Use the trapezium rule with four strips to find an estimate for

${\int }_0^2{2}^{x}dx$

Give your answer to four decimal places.

Given that ${\int }_0^2{2}^{x}dx=\frac{3}{\ln 2}$, find the percentage error in the estimate found in part (a). Give your answer to two significant figures.

Explain, with reference to the shape of the curve $y=2^x$, why the trapezium rule gives an overestimate here.