document.write( "Question 858205: Hi, I am terrible at systems of equations and I have an applications of derivatives assignment with a few questions, the only one dealing with systems of equations is as follows:\r
\n" );
document.write( "\n" );
document.write( "For the function f(x)= ax^4 + bx^3 - 4x^2 + 2cx + 14
\n" );
document.write( "Determine the values of a, b, and c, such that,
\n" );
document.write( "f(-2)=2 , f'(-2)=16 , and f''(-2)=-8\r
\n" );
document.write( "
\n" );
document.write( "\n" );
document.write( "I have tried only messing around with various numbers in my calculator for the past hour to get any number to match with the given values, and I failed\r
\n" );
document.write( "\n" );
document.write( "Any help would be much appreciated
\n" );
document.write( "Thanks \n" );
document.write( "
Algebra.Com's Answer #517103 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! For the function f(x)= ax^4 + bx^3 - 4x^2 + 2cx + 14 \n" ); document.write( "Determine the values of a, b, and c, such that, \n" ); document.write( "f(-2)=2 , f'(-2)=16 , and f''(-2)=-8 \n" ); document.write( "------- \n" ); document.write( "f(x)= ax^4 + bx^3 - 4x^2 + 2cx + 14 \n" ); document.write( "f(-2) = 16a - 8b -16 - 4c + 14 = 2 \n" ); document.write( "16a - 8b - 4c = 4 \n" ); document.write( "4a - 2b - c = 1 Eqn 1 \n" ); document.write( "---- \n" ); document.write( "f(x)= ax^4 + bx^3 - 4x^2 + 2cx + 14 \n" ); document.write( "f'(x) = 4ax^3 + 3bx^2 - 8x + 2c \n" ); document.write( "f'(-2) = -32a + 12b + 16 + 2c = 16 \n" ); document.write( "16a - 6b - c = 0 Eqn 2 \n" ); document.write( "---------- \n" ); document.write( "f''(x) = 12ax^2 + 6bx - 8 \n" ); document.write( "f''(-2) = 48a - 12b - 8 = -8 \n" ); document.write( "4a - b = 0 Eqn 3 \n" ); document.write( "------ \n" ); document.write( "b = 4a \n" ); document.write( "Sub for b in Eqns 1 & 2 \n" ); document.write( "--- \n" ); document.write( "4a - 2b - c = 1 Eqn 1 \n" ); document.write( "4a - 8a - c = 1 \n" ); document.write( "4a + c = -1 Eqn A \n" ); document.write( "--- \n" ); document.write( "16a - 6b - c = 0 Eqn 2 \n" ); document.write( "16a - 24a - c = 0 \n" ); document.write( "8a + c = 0 \n" ); document.write( "c = -8a \n" ); document.write( "---- \n" ); document.write( "Sub for c in Eqn A \n" ); document.write( "4a + c = -1 Eqn A \n" ); document.write( "4a - 8a = -1 \n" ); document.write( "a = 1/4 \n" ); document.write( "------- \n" ); document.write( "c = -2 \n" ); document.write( "b = -1 \n" ); document.write( " |