$\"\"$

The function is $\"\"$ .

How many zeros does the above function have in the interval $\"\"$ .

From $\"\"$ the value of $\"\"$

Period $\"\"$

Substitute $\"\"$ in the above function .

Period $\"\"$ .

The function $\"\"$ completes one cycle in the interval $\"\"$ .

And in the interval $\"\"$ cosine function have two zeros.

Therefore the cosine function have $\"\"$ intervals in the interval $\"\"$ .

In every interval cosine function has two zeros ,hense total no.of zeros in the interval $\"\"$ of the function $\"\"$ is $\"\"$ .

$\"\"$

$\"\"$ zeros