Evaluate y= (1/2)[ (2x^3)/(3) + 4x^2 + 8x ] @ x= 3
I keep getting the answer 39, but the book answer is 78, anyone know why?
2007-07-22 11:59:04 · 4 answers · asked by superman 4 in Science & Mathematics ➔ Mathematics
y= (1/2)[ (2x^3)/(3) + 4x^2 + 8x ]
y=.5*((2*3^3)/3+(4*3^2)+8*3) //substitute for x
y=.5*((2*27)/3+(4*9)+8*3) //reduce powers
y=.5*(54/3+36+24) // reduce multiplications inside parenthesis
y=.5*(18+36+24) //reduce division
y=.5*78 //reduce addition
y=39 //looks like the book is wrong!
PS I used a graphing calculator to check the answer. Are you sure you copied the question right?
2007-07-22 12:07:20 · answer #1 · answered by Anonymous · 0⤊ 0⤋
0.5(2*27/3 + 4*9+8*3)=
.5(18+36+24)= .5(78)=39
the book's answer may have a typographical error
2007-07-22 12:08:02 · answer #2 · answered by 037 G 6 · 0⤊ 0⤋
its 39 the book must have forgotten to multiply by 1/2 at the end.
2007-07-22 12:06:51 · answer #3 · answered by Anonymous · 0⤊ 0⤋
u r right
2007-07-22 12:03:52 · answer #4 · answered by Anonymous · 0⤊ 0⤋