How do you evaluate #cos(cos^-1(1.1))#? Trigonometry Inverse Trigonometric Functions Basic Inverse Trigonometric Functions 1 Answer Andrea S. Dec 1, 2016 #cos(cos^-1(1.1))# cannot be evaluated Explanation: #y=cos^-1(x)# is defined as the number #y# for which #cos y = x#. As the range of #cos x# is #[-1,1]# there is no number for which #cos y = 1.1# Therefore #cos(cos^-1(1.1))# is not defined. Answer link Related questions What are the Basic Inverse Trigonometric Functions? How do you use inverse trig functions to find angles? How do you use inverse trigonometric functions to find the solutions of the equation that are in... How do you use inverse trig functions to solve equations? How do you evalute #sin^-1 (-sqrt(3)/2)#? How do you evalute #tan^-1 (-sqrt(3))#? How do you find the inverse of #f(x) = \frac{1}{x-5}# algebraically? How do you find the inverse of #f(x) = 5 sin^{-1}( frac{2}{x-3} )#? What is tan(arctan 10)? How do you find the #arcsin(sin((7pi)/6))#? See all questions in Basic Inverse Trigonometric Functions Impact of this question 6669 views around the world You can reuse this answer Creative Commons License