How do you evaluate tan ^ -1 ( -1)? Trigonometry Inverse Trigonometric Functions Inverse Trigonometric Properties 1 Answer Shwetank Mauria Oct 22, 2016 tan^(-1)=-pi/4 Explanation: As tan(pi/4)=1 and tan(-theta)=-tantheta tan(-pi/4)=-1 and tan^(-1)=-pi/4 Answer link Related questions How do you use the properties of inverse trigonometric functions to evaluate tan(arcsin (0.31))? What is \sin ( sin^{-1} frac{sqrt{2}}{2})? How do you find the exact value of \cos(tan^{-1}sqrt{3})? How do you evaluate \sec^{-1} \sqrt{2} ? How do you find cos( cot^{-1} sqrt{3} ) without a calculator? How do you rewrite sec^2 (tan^{-1} x) in terms of x? How do you use the inverse trigonometric properties to rewrite expressions in terms of x? How do you calculate sin^-1(0.1)? How do you solve the inverse trig function cos^-1 (-sqrt2/2)? How do you solve the inverse trig function sin(sin^-1 (1/3))? See all questions in Inverse Trigonometric Properties Impact of this question 4134 views around the world You can reuse this answer Creative Commons License