# Trigonometry

## acos¶

Syntax: acos x (unary, atomic)

Returns the arccosine of x; that is, the value whose cosine is x. The result is in radians and lies between 0 and π. (The range is approximate due to rounding errors).

Null is returned if the argument is not between -1 and 1.

q)acos -0.4
1.982313


## asin¶

Syntax: asin x (unary, atomic)

Returns the arcsine of x; that is, the value whose sine is x. The result is in radians and lies between $-\frac{\pi}{2}$ and $\frac{\pi}{2}$. (The range is approximate due to rounding errors).

Null is returned if the argument is not between -1 and 1.

q)asin 0.8
0.9272952


## atan¶

Syntax: atan x (unary, atomic)

Returns the arctangent of x; that is, the value whose tangent is x. The result is in radians and lies between $-{\pi}{2}$ and ${\pi}{2}$. The range is approximate due to rounding errors.

q)atan 0.5
0.4636476
q)atan 42
1.546991


## cos¶

Syntax: cos x (unary, atomic)

Returns the cosine of x, taken to be in radians. The result is between -1 and 1, or null if the argument is null or infinity.

q)cos 0.2
0.9800666
q)min cos 10000?3.14159265
-1f
q)max cos 10000?3.14159265
1f


## sin¶

Syntax: sin x

Returns the sine of x, taken to be in radians. The result is between -1 and 1, or null if the argument is null or infinity.

q)sin 0.5
0.4794255
q)sin 1%0
0n


## tan¶

Syntax: tan x (unary, atomic)

Returns the tangent of x, taken to be in radians. Integer arguments are promoted to floating point. Null is returned if the argument is null or infinity.

q)tan 0 0.5 1 1.5707963 2 0w
0 0.5463025 1.557408 3.732054e+07 -2.18504 0n