*Shape of y versus x graph

Let a physical quantity y depends on other physical quantity x, this dependence is called a mathematical function & usually expressed as

y = f (x) (read as y is a function of x).

The dependence of y on x can be visualised by drawing a graph of function y = f (x). While plotting graphs the independent varaible is taken on horizontal line & dependent on vertical line. Shape of y versus x graph depends on the type of function.

Following types of y versus x graphs are frequently encountered in Physics.

*Transformation formulae 

sinA + sinB = 2sinC cosD

sinA – sinB = 2cosC sinD

cosA + cosB = 2cosC cosD

cosA – cosB = – 2sinC sinD