"After exponential quantities the circular functions, sine and cosine, should be considered because they arise when imaginary quantities are involved in the exponential."

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The World is not an idea as asserted by philosophers who have dedicated their entire lives to the exploration of ideas. First and foremost the world is passion. But passion is associated with sadness. Sadness does not only arise from death which makes us face the Eternity, but also from life which causes us to confront the Time.

— Nikolai Berdyaev