What is the period of #f(t)=cos 2 t #? Trigonometry Graphing Trigonometric Functions Amplitude, Period and Frequency 1 Answer sente Dec 17, 2015 #pi# Explanation: The period of #cos(x)# is #2pi#, thus the period of #cos(2t)# is the change needed in #t# for #2t# to change by #2pi#. So #2t = 2pi => t = pi#. Thus the period is #pi#. Answer link Related questions How do you find the period and frequency of a sine function? How does amplitude relate to the unit circle? How do you calculate the period and frequency? How can amplitude be negative? How do the frequency and period relate to each other? How do you find the amplitude of a cosine function? What is the amplitude of the function #y=-3sin x#? What is the amplitude for the function #y=6sinx#? How do you find the amplitude and period of the function? Do period and frequency depend on amplitude? See all questions in Amplitude, Period and Frequency Impact of this question 4975 views around the world You can reuse this answer Creative Commons License