Question

The longest period of 4cos ³x - 3cos x is ?
1. \(\frac{2\pi}{3}\)
2. π 
3. \(​​\frac{\pi}{3}\)
4. none of above

Answer 1

Correct Answer - Option 1 : \(\frac{2\pi}{3}\)

Concept:

 Period of a function:

• If a function repeats over at a constant period we say that is a periodic function.
• It is represented like f(x) = f(x + T), T is the real number and this is the period of the function.
• The period of sin x and cos x is 2π

 

Calculation:

To Find: Period of 4cos ³x - 3cos x 

As we know 4cos ³x - 3cos x  = cos 3x

Period of cos x is 2π

Therefore, the Period of cos 3x is \(\frac{2\pi}{3}\)2π3