Find the cosine function that is represented in the graph.

Answer:f(x)=4cos(5x)Step-by-step explanation:Let us see the standard form of cosine function f(x) = acos(nx)Where x is the angle in radians along x axis for x=0 , we see that the value of f(x) = 4Hence acos(n*0)=4            acos 0 = 4            a *1 = 4    (as cos 0 = 1) Hence we have a = 4 , therefore our equation becomes f(x) = 4 cos (nx)from the given graph we can see that for x = [tex]\frac{\pi }{5}[/tex]   f(x) = -4 Hence [tex]4cos(\frac{n\pi}{5}) = -4[/tex]dividing both sides by 4 we get [tex]cos(\frac{n\pi}{5} )=-1\\cos(\frac{n\pi}{5})=cos \pi\\Hence \\\frac{n\pi}{5}=\pi\\n\pi= 5\pi\\n=5[/tex]Hence we have value of n also as 5Hence our function is f(x) = [tex]4cos(5x)[/tex]