Ok this is the product rule with respect to cosign and sign which I’m going to show you and we get started to get to my menu you have to press second alpha and enter the letters i n d e x and then press alpha again to put the eight and the open and closed parenthesis press enter and you are into my menu you scroll up or where ever you want but I want to dot product rule right now so were going to do that one I give you the formula write all this stuff down on your paper or test whatever it’s always good to write use all parenthesis lot of parenthesis and you have to press alpha before you enter anything in my entry lines here and you have to enter it in this form here parenthesis with a times sign and parenthesis so were going to press alpha left parenthesis and put a function in here press the gold key for cosign five time x close off the parenthesis times sign add the other parenthesis and put gold key sign five times x cubed and then press enter. I always show you what you’ve entered so you can change it if you want give you the option there on the next screen. I say it’s ok. I show you what f of x is and g of x is and then you apply it to the formula and keep working the problem write down everything you see on your paper and you get a hundred percent on this problem and here’s the answer five x squared cosign of five x times cosign of five x and then minus five sign of five x sign of five see you write this down hundred percent on your paper. Pretty neat huh? everystepcalculus.com. Go to my site buy my programs and pass calculus.