Answer with explanation:
The given cosine function is
y= - cos 3 (theta)= -3 cos A, where , theta =A.
→→Domain of Cos A
= All Real number
= Period is from (-π , π)
Range of Cos A=[-1, 1]
→Domain of Cos 3 A,will be also, all real number.
Period is from,
[tex][\frac{-\pi}{3},\frac{\pi}{3}][/tex]
But range of Cos 3A,will be same as ,Cos A which is equal to ,[-1,1].
→Plotted the graph of ,y=-cos 3 A, having cycle ,
[tex][\frac{-\pi}{3},\frac{\pi}{3}][/tex]
