ref: 26d36c3ae2fd6ae40148be58589ea5e81b0ca341
dir: /sys/src/cmd/postscript/tests/troff1/
.EQ delim $$ .EN .TS doublebox; c c l l. Name Definition .sp .vs +2p Gamma $GAMMA (z) = int sub 0 sup inf t sup {z-1} e sup -t dt$ Sine $sin (x) = 1 over 2i ( e sup ix - e sup -ix )$ Error $ roman erf (z) = 2 over sqrt pi int sub 0 sup z e sup {-t sup 2} dt$ Bessel $ J sub 0 (z) = 1 over pi int sub 0 sup pi cos ( z sin theta ) d theta $ Zeta $ zeta (s) = sum from k=1 to inf k sup -s ~~( Re~s > 1)$ .vs -2p .sp 2 .TE