N tuning forks are arranged in order of increasing frequency and any two successive tuning forks give n beats per second when sounded together. If the last fork gives double the frequency of the first (called as octave), Show that the frequency of the first tuning fork is `f=(N-1)n`.

Explanation

`f,f+n, f+2n, ...f +(m-1)n`
`f+(N-1)n=2f`
`n=(f)/(N-1)`
`(or) f=n(N-1)`