If , then the values of form a series in
Thus the values of form an A.P. with common difference .
The number of solutions of the equation
If n be the number of solutions of the equation
, then n =
The values of x between 0 and which satisfy the equation
are in A.P. The common difference of the A.P.
The number of pairs (x, y) satisfying the equations
The smallest +ive x such that
The general solution of the trigonometrical equation
is given by
The general solution of equation
The solution set of in the interval
then the value of x other than zero, lying between is