Radio Shack TRS-80 PC-3 Owner's Manual page 181

1 SGN numeric expression
SGN is a numeric function which returns a value based on the sign of the argument. If the argument is positive, the result is 1; if
the argument is zero, the result is 0; if the argument is negative, the result is
-1.
SGN
-5
is
-1.
1 SIN numeric expression
SIN is a numeric function which returns the sine of the angle argument. The value returned depends on whether the PC-3 Com-
puter is in decimal degree, radian, or gradient mode for angles. SIN 30 is .5
1 SOR numeric expression
SQR is a numeric function which returns the square root of its argument. It is identical to the use of the special square root symbol
(V) on the keyboard. SQR 4 is 2.
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