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## 3.9 Trigonometric Functions

real hypot(real x, real y)
Return the length of the hypotenuse of a right triangle with sides of length x and y. $\text{hypot}(x,y) = \begin{cases} \sqrt{x^2+y^2} & \text{if } x,y\geq 0 \\ \textrm{NaN} & \text{otherwise} \end{cases}$

R cos(T x)
cosine of the angle x (in radians)

R sin(T x)
sine of the angle x (in radians)

R tan(T x)
tangent of the angle x (in radians)

R acos(T x)
principal arc (inverse) cosine (in radians) of x

R asin(T x)
principal arc (inverse) sine (in radians) of x

R atan(T x)
principal arc (inverse) tangent (in radians) of x, with values from $$-\pi$$ to $$\pi$$

real atan2(real y, real x)
Return the principal arc (inverse) tangent (in radians) of y divided by x, $\text{atan2}(y, x) = \arctan\left(\frac{y}{x}\right)$