Solution
= Solution
Two strips give $h=\pi/4$, with cosine values $1,1/\sqrt2,0$. The <trapezoidal rule> therefore gives
$$
T_2=\frac\pi8(1+\sqrt2)=0.948059\ldots=\boxed{0.948}.
$$
The exact integral is $1$, so the estimate is low, consistent with the concavity of cosine on this interval. The table can be used as $T_2=\tfrac12(0.7854)+0.5554$ before rounding.