How do you find the value of #cot2theta# given #cottheta=4/3# and #pi<theta<(3pi)/2#? Trigonometry Trigonometric Identities and Equations Double Angle Identities 1 Answer Shwetank Mauria Jul 21, 2016 #cot2theta=7/24# Explanation: #cot2theta=(cot^2theta-1)/(2cottheta)# = #((4/3)^2-1)/(2xx4/3)# = #(16/9-1)/(8/3)# = #((16-9)/9)/(8/3)# = #7/9xx3/8# = #7/(3cancel9)xx(1cancel3)/8# = #7/24# Answer link Related questions What are Double Angle Identities? How do you use a double angle identity to find the exact value of each expression? How do you use a double-angle identity to find the exact value of sin 120°? How do you use double angle identities to solve equations? How do you find all solutions for #sin 2x = cos x# for the interval #[0,2pi]#? How do you find all solutions for #4sinthetacostheta=sqrt(3)# for the interval #[0,2pi]#? How do you simplify #cosx(2sinx + cosx)-sin^2x#? If #tan x = 0.3#, then how do you find tan 2x? If #sin x= 5/3#, what is the sin 2x equal to? How do you prove #cos2A = 2cos^2 A - 1#? See all questions in Double Angle Identities Impact of this question 4161 views around the world You can reuse this answer Creative Commons License