Proofs of sum of two even numbers is even

Problem Show that the sum of two even numbers is also an even number. Solutions 1. Good for 1/5 mark 2 + 4 = 6      6 + 8 = 14, 2+8 = 10      20 + 30 = 50 24 + 10 = 34. There’s no two even number I can think

Solving problems by equations and graphs

Problems need not always be solved by equations alone. Problems that involve setting up equations can be solved using graphs also. This requires knowledge of interpreting equations in x as a function of x. This is an important knowledge as it will be handy in solving problems in calculus.  The key to the solution of

How to sketch the graph of the derivative of a function

What is a derivative function? The derivative function f  is a function f’ that maps each value of x to the gradient or slope of the line tangent to f(x). Let’s have an example. Suppose your function f is defined by f(x)=x2. The derivative of f is the function f’ defined by f’(x) =2x. This