document.write( "Question 1032139: Consider the function y = f(x) ={( x + 1/ x - 2)}^3
\n" ); document.write( "(a) Find the derivative of f.
\n" ); document.write( "(b) Find the equations of the tangent and the normal to the curve y = f(x) at the point (1,-8).
\n" ); document.write( "(c) Find all the values of x so that f'(x) < 0.
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Algebra.Com's Answer #646812 by robertb(5830)\"\" \"About 
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(a) \"y+=+f%28x%29+=+%28+%28x+%2B+1%29%2F%28+x+-+2%29%29%5E3+\"\r
\n" ); document.write( "\n" ); document.write( "==> y' = \r
\n" ); document.write( "\n" ); document.write( "= \"%28-9%28x%2B1%29%5E2%29%2F%28x-2%29%5E4\"\r
\n" ); document.write( "\n" ); document.write( "(b) f'(1) = -36 after substitution into the previous equation for y'.\r
\n" ); document.write( "\n" ); document.write( "==> the equation of the tangent at (1, -8) is \"y%5Bt%5D+%2B+8+=+-36%28x-1%29\", or
\n" ); document.write( "\"y%5Bt%5D+=+-36x+%2B+28\".\r
\n" ); document.write( "\n" ); document.write( "==> the equation of the normal at (1, -8) is \"y%5Bn%5D+%2B+8+=+%281%2F36%29%28x-1%29\", or
\n" ); document.write( "\"y%5Bn%5D+=+%281%2F36%29x+-+289%2F36\" after simplification.\r
\n" ); document.write( "\n" ); document.write( "(c) f'(x) < 0 for all real values EXCEPT at x = 2, where there is an essential (infinite) discontinuity. (This is because f'(x) = \"%28-9%28x%2B1%29%5E2%29%2F%28x-2%29%5E4+%3C+0\" except at x=2 where it is undefined.)
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