Question

Using the quotient rule, find the derivation of the following function:

a) (ax^2+b)/(cx+d)

Here is my work but i need help because am lit bit confuse

solution
a) (ax^2+b)/(cx+d)
df/dx = (2ax)(cx+d)-(ax^2+b) (c)/(cx+d)^2

df/dx = 2acx^2+2adx-acx^2+bc/(cx+d)^2

df/dx =acx^2+2adx+bc/(cx+d)^2

df/dx = c(ax^2+b)+ 2adx/(cx+d)^2

df/dx = ax^2+b+2ax/cx^2+d

Answer 1

[ bottom d top/dx - top d bottom/dx]/bottom^2

[(cx+d)(2ax) - (ax^2+b)(c)] /(cx+d)^2 agree

= [2acx^2+2adx - acx^2-bc] /(cx+d)^2
disagree sign of bc

= [acx^2 + 2adx - bc ] /(cx+d)^2