Inverse trig functionsDate: Wed, 14 Dec 1994 15:17:46 -0500 (EST) From: Lizzy Hechenbleikner Subject: Calculus Help I am trying to evaluate this: cot[sin^-1 (-1) + 2sec^-1 (-2)] In other words... cotangent of inverse sine of negative one plus two times inverse secant of negative 2. Please help, thanks Date: Wed, 14 Dec 1994 17:21:39 -0500 (EST) From: Dr. Ken Subject: Re: Calculus Help Hello there! Basically, this problem revolves on your ability to deal with the inverse trigonometric functions. For instance, to evaluate Sin^-1 (-1), you ask yourself "what angle has a Sine of -1?" If you look at the graph of the Sine function, or at the unit circle, you see that the angle -90 degrees has the right Sine. So this is that part of the answer. Then to find Sec^-1 (-2), you remember that Secant is the reciprocal of Cosine. So you ask yourself "what angle has a cosine of 1/2?" Then you look at the unit circle, and you say "Aha! It's 60 degrees! Pi/3 radians!" So this is that part of the answer. Then you have Cot[-90 + 2*60] = Cot[30] = 1/Tan[30] = Sqrt{3}. I hope this helps you out, and write back if you need more help! -Ken "Dr." Math |
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