yuemingl
diff --git a/Collapse file
‎.classpath‎
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+1-1Lines changed: 1 addition & 1 deletion b/Collapse file
‎.classpath‎
Copy file name to clipboardExpand all lines: .classpath
+1-1Lines changed: 1 addition & 1 deletion
diff --git a/Collapse file
‎src/symjava/symbolic/Expr.java‎
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+1-1Lines changed: 1 addition & 1 deletion b/Collapse file
‎src/symjava/symbolic/Expr.java‎
Copy file name to clipboardExpand all lines: src/symjava/symbolic/Expr.java
+1-1Lines changed: 1 addition & 1 deletion
@@ -2,6 +2,6 @@
 <classpath>
 	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="lib" path="lib/Jama-1.0.3.jar"/>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/java-7-oracle"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>
@@ -25,7 +25,7 @@ public Expr fdiff(Expr f, Expr df) {
 			throw new IllegalArgumentException();
 		Func F = (Func)f;
 		Symbol alpha = new Symbol("_alpha_");
-		Expr ff = this.subs(f, f+alpha*df);
+		Expr ff = this.subs(f, f.add(alpha.multiply(df)));
 		Expr dff = ff.diff(alpha);
 		if(Symbol.C0.symEquals(dff)) {
 			Func ret = new Func("0", F.args);