− π 2 {\displaystyle {\frac {-\pi }{2}}} ⋅ {\displaystyle \cdot } c a n c e l 2 ⋅ 2 ⋅ 5 ⋅ 3 ⋅ 3 π {\displaystyle {\frac {cancel2\cdot 2\cdot 5\cdot 3\cdot 3}{\pi }}}