How do I find the value of #sec (4pi)#? Trigonometry Right Triangles Trigonometric Functions of Any Angle 1 Answer Rhys Jun 25, 2018 #sec(4pi) = 1 # Explanation: Note that #sectheta = 1/costheta # #=> sec (4pi) = 1/cos(4pi) # #cos4pi = 1 # #=> sec(4pi) = 1/1 = 1 # Answer link Related questions How do you find the trigonometric functions of any angle? What is the reference angle? How do you use the ordered pairs on a unit circle to evaluate a trigonometric function of any angle? What is the reference angle for #140^\circ#? How do you find the value of #cot 300^@#? What is the value of #sin -45^@#? How do you find the trigonometric functions of values that are greater than #360^@#? How do you use the reference angles to find #sin210cos330-tan 135#? How do you know if #sin 30 = sin 150#? How do you show that #(costheta)(sectheta) = 1# if #theta=pi/4#? See all questions in Trigonometric Functions of Any Angle Impact of this question 7219 views around the world You can reuse this answer Creative Commons License