atan()
Return the arctangent of the argument.
Syntax
atan(tangent)
Parameter
Parameter | Definition |
|---|---|
tangent | tangent argument*Valid Values* |
Description
The atan() function returns the arctangent of tangent, that is, the length in radians of the arc whose tangent is tangent. The output range for the atan() function is -p/2 ≤ atan() ≤ p/2.
Example
The following example uses atan() to verify the trigonometric identity:
print("Arcsine(Arctangent) Identity Verification\n\n");
print(" tan() Expected Returned\n");
print("--------- --------- ---------\n");
tangent = -1.5;
while (tangent <= 1.5){
expect = tangent / sqrt(1 + pow(tangent,2));
printf("%+8.6f %+8.6f %+8.6f\n",tangent,expect,sin(atan(tangent)));
tangent = tangent + 0.1;
}
print(" tan() Expected Returned\n");
print("--------- --------- ---------\n");
tangent = -1.5;
while (tangent <= 1.5){
expect = tangent / sqrt(1 + pow(tangent,2));
printf("%+8.6f %+8.6f %+8.6f\n",tangent,expect,sin(atan(tangent)));
tangent = tangent + 0.1;
}
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