Write the value of `theta in (0, pi/2)` for which area of the triangle formed by points `O(0,0), A(a costheta, b sintheta) `and `B(a costheta, -b sintheta)` is maximum.

Explanation

Given`O(0,0), A(a costheta, b sintheta)`and `B(acostheta, -b sintheta)`


Area=`1/2[x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)]`

=`1/2[acostheta(-bsintheta)+acostheta(-bsintheta)]`

=`abcosthetasintheta`

For maximum `theta =pi/4`

or area=`1/2ab`