6.13.1 `dacos', `dasin', `datan', `dcos', `dsin', `dtan'
--------------------------------------------------------

dacos(NUM)
     :: $BH!?tCM(B Arccos(NUM) $B$r5a$a$k(B.

dasin(NUM)
     :: $BH!?tCM(B Arcsin(NUM) $B$r5a$a$k(B.

datan(NUM)
     :: $BH!?tCM(B Arctan(NUM) $B$r5a$a$k(B.

dcos(NUM)
     :: $BH!?tCM(B cos(NUM) $B$r5a$a$k(B.

dsin(NUM)
     :: $BH!?tCM(B sin(NUM) $B$r5a$a$k(B.

dtan(NUM)
     :: $BH!?tCM(B tan(NUM) $B$r5a$a$k(B.

RETURN
     $BG\@:EYIbF0>.?t(B

NUM
     $B?t(B

   * $B;03Q4X?t!"5U;03Q4X?t$r?tCME*$K7W;;$9$k(B.

   * $B$3$l$i$NH!?t$O(B C $B8@8l$NI8=`?t3X%i%$%V%i%j$rMQ$$$k(B.  $B$7$?$,$C$F(B,
     $B7W;;7k2L$O%*%Z%l!<%F%#%s%0%7%9%F%`$H%3%s%Q%$%i$K0MB8$9$k(B.

   * $BJ#AG?t$KBP$7$F$O@5$7$/$J$$7k2L$rJV$9$N$GCm0U$7$J$1$l$P$J$i$J$$(B.

   * @pi $B$J$I$N%7%s%\%k$r0z?t$KM?$($k$3$H$O$G$-$J$$(B.

     [0] 4*datan(1);
     3.14159

