1. What is the smallest value of [unparseable or potentially dangerous latex formula] if the area under the curve [unparseable or potentially dangerous latex formula] from -infinity to 4 is equal to 11?
2. A rectangleis bounded by the x-axis and the semicircle [unparseable or potentially dangerous latex formula]. Find the height of the rectangle of maximum area.
3. [unparseable or potentially dangerous latex formula]
4. [unparseable or potentially dangerous latex formula]