(************************************************************************) (* v * The Coq Proof Assistant / The Coq Development Team *) (* R); x0,x1:R) ``((f x1)-(f x0))*1/(x1-x0)+((g x1)-(g x0))*1/(x1-x0) == ((f x1)+ (g x1)-((f x0)+(g x0)))*1/(x1-x0)``. Proof. Intros. Field. Abort. (* Example 3 *) Goal (a,b:R)``1/(a*b)*1/1/b == 1/a``. Proof. Intros. Field. Abort. (* Example 4 *) Goal (a,b:R)``a <> 0``->``b <> 0``->``1/(a*b)/1/b == 1/a``. Proof. Intros. Field. Abort. (* Example 5 *) Goal (a:R)``1 == 1*1/a*a``. Proof. Intros. Field. Abort. (* Example 6 *) Goal (a,b:R)``b == b*/a*a``. Proof. Intros. Field. Abort. (* Example 7 *) Goal (a,b:R)``b == b*1/a*a``. Proof. Intros. Field. Abort. (* Example 8 *) Goal (x,y:R)``x*((1/x)+x/(x+y)) == -(1/y)*y*(-(x*x/(x+y))-1)``. Proof. Intros. Field. Abort.