document.write( "Question 1001594: Please check my answers:\r
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document.write( "Q: Let f(x) = 2x^3 - 3x^2 + 6. Find the max and min values of f on [-1,1]\r
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document.write( "A: f'(x) = 6x^2 - 6x
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document.write( "= 6x(x - 1) =0
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document.write( "x=0, x=+1 critical values. However, +1 is already there so 2nd der test is not needed.\r
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document.write( "f\"(x) = 12x-6
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document.write( "f\"(0) = 12(0)-6=-6<0, therefore a MIN occurs at 0.\r
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document.write( "plugging in the x-values given.
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document.write( "f(1) = 2(1)^3-3(1)^2+6 = 5
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document.write( "f(-1) = 2(-1)^3-3(-1)^2+6 = 1\r
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document.write( "After graphing it looks like (-1,7) is the MIN and (0,6) is the MAX.\r
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document.write( "Is this correct?\r
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document.write( "Thank you \n" );
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Algebra.Com's Answer #618722 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! 2nd Derivative Test: if f '' (x) is negative on some interval, then the region on f(x) is concave DOWN (not up). So we have a max on this interval. That means a local max is at x = 0.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I think you meant to say (-1,1) instead of (-1,7)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Summary: \n" ); document.write( "Local Max = (0,6) \n" ); document.write( "Local Min = none \n" ); document.write( "Absolute Max = (0,6) \n" ); document.write( "Absolute Min = (-1,1) \n" ); document.write( " |