document.write( "Question 1198723: Given cot theta =-2 and csc theta < 0, find sin theta and sec theta \n" ); document.write( "
Algebra.Com's Answer #832552 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "In response to what the tutor @MathLover1 wrote: Cotangent is NOT negative in quadrant Q3. \n" ); document.write( "Take note how sine and cosine are indeed negative here, so, \n" ); document.write( "cot = cos/sin \n" ); document.write( "the two negative items divide to a positive result.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In short, cotangent is positive in Q3.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since cot(theta) = -2 is negative, this places theta in either Q2 or Q4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then we're told csc(theta) < 0, which fully narrows things down to Q4 only. \n" ); document.write( "270 < theta < 360 in degree mode \n" ); document.write( "3pi/2 < theta < 2pi in radian mode \n" ); document.write( "The actual theta value itself doesn't matter; however, this interval helps narrow things down a bit.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since cot(theta) = -2 = 2/(-1), we could have a triangle with adjacent side 2 and opposite side -1. \n" ); document.write( "I'll make the opposite length \"negative\" so that we can keep the proper signs in mind. Of course a negative length isn't possible. \n" ); document.write( "It's purely as a means to retain information. \n" ); document.write( "I'm making the 1 negative so that it indicates we're below the x axis, i.e. the y coordinate is negative.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Use the pythagorean theorem to find the hypotenuse is sqrt(5) units long.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This is one way to draw the triangle in Q4 \n" ); document.write( " ![]() \n" ); document.write( "We have: \n" ); document.write( "opposite = -1 \n" ); document.write( "adjacent = 2 \n" ); document.write( "hypotenuse = sqrt(5)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then recall that \n" ); document.write( "sin(theta) = opposite/hypotenuse \n" ); document.write( "sec(theta) = hypotenuse/adjacent\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I'll let you finish up from here. \n" ); document.write( " \n" ); document.write( " |