Some ways to catch a lion

1st way
the calculus method

Differentiate the entire jungle in which the Lion is hiding and then integrate it with respect to the lion.

2nd way
Newtons 3rd law

Allow the Lion to catch you and since to every action there is equal and opposite reaction (according to newton's third law) the Lion gets caught himself.

3rd way
Biological way

Prepare a semi-permeable membrane which will allow everything in the world to pass through it except the Lion. Sieve the jungle using the membrane to catch the Lion.

4th way
Laplace Inverse Transform

Put a cage in the jungle and lock it properly. Sit inside the cage. When you spot the Lion perform the Laplace inverse transform from cage domain to jungle domain so that you get out and the Lion gets caught inside the cage.