Appendix B

Mathematical Functions

Mathematical functions not intrinsic to BASIC can be calculated as follows:

Function	BASIC Equivalent
Secant	SEC(X)=1/COS(X)
Cosecant	CSC(X)=1/SIN(X)
Cotangent	COT(X)=1/TAN(X)
Inverse Sine	ARCSIN(X)=ATN(X/SQR(-X*X+1))
Inverse Cosine	ARCCOS(X)=ATN (X/SQR(-X*X+1))+ PI/2
Inverse Secant	ARCSEC(X)=ATN(X/SQR(XX-1))+SGN(SGN(X)-1) PI/2
Inverse Cosecant	ARCCSC(X)=ATN(X/SQR(XX-1))+SGN(X)-1) PI/2
Inverse Cotangent	ARCCOT(X)=ATN(X)+ PI/2
Hyperbolic Sine	SINH(X)=(EXP(X)-EXP(-X))/2
Hyperbolic Cosine	COSH(X)=(EXP(X)+EXP(-X))/2
Hyperbolic Tangent	TANH(X)=EXP(X)-EXP(-X))/+(EXP(X)+EXP(-X))
Hyperbolic Secant	SECH(X)=2/(EXP(X)+EXP(-X))
Hyperbolic Cosecant	CSCH(X)=2/(EXP(X)-EXP(-X))
Hyperbolic Cotangent	COTH(X)=EXP(-X)/(EXP(X)-EXP(-X))*2+1
Inverse Hyperbolic Sine	ARCSINH(X)=LOG(X/SQR(X*X+1))
Inverse Hyperbolic Cosine	ARCCOSH(X)=LOG(X+SQR(X*X-1))
Inverse Hyperbolic Tangent	ARCTANH(X)=LOG((1+X)/(1-X))/2
Inverse Hyperbolic Cosecant	ARCCSCH(X)=LOG(SGN(X)SQR(XX+1)+1)/X
Inverse Hyperbolic Secant	ARCSECH(X)=LOG(SQR(-X*X+1)+1)/X
Inverse Hyperbolic Cotangent	ARCCOTH(X)=LOG((X+1)/(X-1))/2