Cosines represent the ratio of the adjacent side to the hypotenuse in a right triangle. They help define wave oscillations, circular motion, and Fourier analysis. The cosine function is periodic, with a range from -1 to 1, and plays a key role in trigonometry, calculus, and physics applications.
Class 12 Maths Chapter 11 Three Dimensional Geometry is an important topic for CBSE Exam 2024-25. It covers concepts like direction cosines and direction ratios of a line equations of a line in different forms shortest distance between two lines equations of a plane angles between planes and distance of a point from a plane.
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The direction cosines of a line are given as k, k, and k. The sum of the squares of the direction cosines must equal 1:
k² + k² + k² = 1
3k² = 1
k² = 1/3
k = ±1/√3
Thus, the correct answer is: k = 1/√3 or -1/√3
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