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What is the value of cos9*?
How did trigonometry develop over time?
Trigonometry has its roots in ancient civilizations such as the Egyptians, Babylonians, and Greeks. The word "trigonometry" itself comes from the Greek words for "triangle" and "measurement". Over time, trigonometry has been developed and refined by mathematicians such as Hipparchus, Ptolemy, and Al-Khwarizmi.