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tan, atan

Tangent and arctangent

tan x     tan[x]
atan x    atan[x]

Where x is a numeric, returns

tan
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.
The function is equivalent to {(sin x)%cos x}.
atan
the arctangent of x; that is, the value whose tangent 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.
q)tan 0 0.5 1 1.5707963 2 0w                    / tangent
0 0.5463025 1.557408 3.732054e+07 -2.18504 0n

q)atan 0.5                                      / arctangent
0.4636476
q)atan 42
1.546991

Implicit iteration

tan and atan are atomic functions.

q)tan (.2;.3 .4)
0.20271
0.3093362 0.4227932

q)atan (.2;.3 .4)
0.1973956
0.2914568 0.3805064

q)tan `x`y`z!3 4#til[12]%10
x| 0         0.1003347 0.20271   0.3093362
y| 0.4227932 0.5463025 0.6841368 0.8422884
z| 1.029639  1.260158  1.557408  1.96476

cos and acos, sin and asin
Mathematics