# The expression $sin^2$ x + $cos^2$ x-1=0 is satisfied by how many values of x?

 [ A ]    Only one value of x [ B ]    Two values of x [ C ]    Infinite values of x [ D ]    No value of x
 Answer : Option C Explanation : Given that, $sin^2$ x + $cos^2$ x-1=0 ==> $sin^2$ x + $cos^2$x=1 which is an identity of trigonometric ratio and always true for every real value of x. Therefore, the equation has an infinite solution.