Radians function. RADIANS(x) converts an angle x expressed in degrees to radians.
The relation between the 2 units is as follows: 2 x Pi radians = 360 degrees.
The argument x can be a real number or a matrix. When it is a matrix, the function returns a matrix with the same dimensions and with the RADIANS function applied to all elements.
RADIANS(90) equals 1.5707963 (=Pi/2)
Trigonometry: A Complete Introduction
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