The function y=3cosleft(frac4x5right)y = 3\\cos\\left(\\frac{4x}{5}\\right)y=3cosleft(frac4x5right) has a period TTT. What is the period?
frac2pi4\\frac{2\\pi}{4}frac2pi4
frac10pi4\\frac{10\\pi}{4}frac10pi4
frac8pi5\\frac{8\\pi}{5}frac8pi5
2pi2\\pi2pi