SOLUTION: Hi, please help me solve this questions. Find the derivatives of the following (a). y= x (x-3)(x+4) (b). y= 7x+17x^2+30x^3 (c). y= 5e^x+9inX-x^9+8

Algebra ->  Equations -> SOLUTION: Hi, please help me solve this questions. Find the derivatives of the following (a). y= x (x-3)(x+4) (b). y= 7x+17x^2+30x^3 (c). y= 5e^x+9inX-x^9+8      Log On


   

Question 1160584: Hi, please help me solve this questions.
Find the derivatives of the following
(a). y= x (x-3)(x+4)
(b). y= 7x+17x^2+30x^3
(c). y= 5e^x+9inX-x^9+8
Found 2 solutions by solver91311, Edwin McCravy:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!









John

My calculator said it, I believe it, that settles it

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
(a). y = x(x-3)(x+4)
Use formula
     y = product of the 1st and 2nd times the derivative of the 3rd
             plus
         product of the 1st and 3rd times the derivative of the 2nd
             plus   
         product of the 2nd and 3rd times the derivative of the 1st
             
dy%2Fdx=x%28x-3%29%281%29%2Bx%28x%2B4%29%281%29%2B%28x-3%29%28x%2B4%29%281%29
dy%2Fdx=x%28x-3%29%2Bx%28x%2B4%29%2B%28x-3%29%28x%2B4%29
dy%2Fdx=%28x%5E2-3x%29%2B%28x%5E2%2B4x%29%2B%28x%5E2%2Bx-12%29
dy%2Fdx=x%5E2-3x%2Bx%5E2%2B4x%2Bx%5E2%2Bx-12
dy%2Fdx=x%5E2%2Bx%5E2%2Bx%5E2-3x%2B4x%2Bx-12
dy%2Fdx=3x%5E2%2B2x-12 

Or multiply it out first

+y+=+x%28x-3%29%28x%2B4%29
y=%28x%5E2-3x%29%28x%2B4%29
y=x%5E3%2B4x%5E2-3x%5E2-12x
y=x%5E3%2Bx%5E2-12x
dy%2Fdx=3x%5E2%2B2x-12

Same answer

(b). y= 7x+17x^2+30x^3
y=+7x%2B17x%5E2%2B30x%5E3
dy%2Fdx=7%2B34x%2B90x%5E2
(c). y= 5e^x+9inX-x^9+8

That makes no sense. Sorry!

Edwin