a revision question asks to solve an intergral by trapezium rule which I'm okay with. However the second part of the question doesnt even make any sense to me (Wondering)

Write down the least value of sec x for 0 <= x <= pi/2. hence show that $\displaystyle

\int_0^a \sqrt{secx } dx > a $ for 0 < a < pi/2

Any ideas?