Alhazen (c. 965 – c. 1040 AD)
Alhazen was a polymath; the author of 90 works on topics as diverse as optics, vision, number theory, geometry, theology, astronomy, poetry, healing, and metaphysics. Many of his works, including the highly influential Book of Optics, were authored while he feigned madness to escape the wrath of Cairo’s caliph.
Alhazen explained how the images formed in cameras are upside down, solved ‘Alhazen’s problem’ concerning the reflection of light from curved surfaces, and discovered a general method to find the sum of any integral power. He used this general method to discover the sum of fourth power positive integers and hence find the volume of a paraboloid..