One of the most esteemed mathematicians of the last century, Johann Friedrich Pfaff is known for his work on partial differential equations of the first order.
The world's first handheld commercially available mobile phone was Motorola's DynaTAC. It was priced at $3,995 upon release and had an LED display for dialling and recalling numbers. Martin Cooper of Motorola made the very first call from a cell phone using the DynaTAC on 3rd April 1973. [more...]