Wrote a few rules

derive2.lisp

@@ -56,6 +56,45 @@
          (loop for (name test expander) in *rules*
             do (if (apply test function)
                    (setf expansion-function expander)))
-         (apply expansion-function (rest function)))))))
+         (if (functionp expansion-function)
+             (apply expansion-function (rest function))
+             (error "Undefined expansion: ~a" op)))))))
+
+(defun csc (x)
+  "csc -- (csc x)
+Calculate the cosecant of x"
+  (/ (sin x)))
+
+(defun sec (x)
+  "sec -- (sec x)
+Calculate the secant of x"
+  (/ (cos x)))
+
+(def-expansion mult/2 (* 2) (first second)
+  (cond
+    ((numberp first)
+     `(* ,first ,(derive (if (listp second) second (list second)))))
+    ((numberp second)
+     `(* ,second ,(derive (if (listp first) first (list second)))))
+    (t
+     `(+ (* ,first ,(derive (if (listp second) second (list second))))
+         (* ,second ,(derive (if (listp first) first (list first))))))))
+
+(def-expansion exp/1 (exp 1) (expression)
+  (if (listp expression)
+      `(* (expt ,expression) ,(derive expression))
+      (if (numberp expression)
+          0
+          `(expt ,expression))))
+
+(def-expansion expt/2 (expt 2) (base exponent)
+  (if (listp base)
+      `(* ,exponent (expt ,base (1- ,exponent)) ,(derive base))
+      `(* ,exponent (expt ,base (1- ,exponent)))))
+
+(def-expansion log/1 (log 1) (expression)
+  `(/ ,(derive (if (listp expression) expression (list expression))) ,expression))
+
+(def-expansion log/2 (log 2) (number base))
 
 ;;; End derive2