Solve, using the product rule, y = (4x-1)(x^2 -5x +1)

Question

anonymous · Answer

The texts answer given is 12x^2 -38x -1

aravindg · Answer

ok do u knw hw to use product rule?

anonymous · Answer

Yes and i've completed the question, but my textbook gives a different answer. I can see where i went wrong, so i just wanted a second opinion :)

anonymous · Answer

I believe that my textbook has given a wrong answer.

aravindg · Answer

wow :)

dy/dx=4(x^2 -5x +1)+(4x-1)(2x-5)
          =4x^2-20x+4+8x^2-20x+2x+5
          =12x^2-38x+9

anonymous · Answer

ah i see, my apologies i am an idiot.

aravindg · Answer

did i make a mistake in constant part or is it ur text ?

anonymous · Answer

I read t as +38x in my text

anonymous · Answer

So i didnt see how it would work at all. Thanks very much, I feel like a complete idiot now. Thanks for the help non-the-less. Have a good one mate!!

aravindg · Answer

yw :)