Consider f:1,2,3→ {a,b,c}given by f(1)=a, f(2)=b and f(3)=c. Find the (f−1)−1 of (f−1) . Show that (f−1)−1=f.
The centre of an equilateral triangle is O. Three forces F1,F2 and F3 are appointed along AB, BC and AC respectively. The magnitude of F3 so that the total torque about O should be zero is