Factoring with Trigonometry
Date: 3/5/96 at 20:38:26 From: Anonymous Subject: A question about trig. Hello, Please will you help me out in math on this one problem. 4tan^2X + 7tanX - 2 = 0 Thanks
Date: 3/6/96 at 13:0:11 From: Doctor Elise Subject: Re: A question about trig. Hi! Okay, don't panic because you have tanX in there. Let's substitute Y = tanX for now, and plug the tanX back in later. Then your problem becomes: 4Y^2 + 7Y - 2 = 0 If we factor this, we get (4Y - 1)(Y + 2) = 0, right? Solving for Y, we know that one or the other term = 0, so either (4Y - 1) = 0 or (Y + 2) = 0 Y = 1/4 or Y = -2 Now we can put back the Y = tanX, and we have tanX = 1/4 or tanX = -2 And now you need a tangent table to find the actual values for X that work. Does this help? -Doctor Elise, The Math Forum
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