How do you find the derivative of (x-3)/(2x+1)x32x+1?

2 Answers
Oct 5, 2017

7/(2x+1)^27(2x+1)2

Explanation:

"differentiate using the "color(blue)"quotient rule"differentiate using the quotient rule

"given "f(x)=(g(x))/(h(x))" then"given f(x)=g(x)h(x) then

f'(x)=(h(x)g'(x)-g(x)h'(x))/(h(x))^2larr" quotient rule"

g(x)=x-3rArrg'(x)=1

h(x)=2x+1rArrh'(x)=2

rArrf'(x)=((2x+1)-2(x-3))/(2x+1)^2

color(white)(rArrf'(x))=7/(2x+1)^2

Oct 5, 2017

=7/(4x^2-4x+1) or 7/(2x+1)^2

Explanation:

Quotient rule: (u'v )-(uv') all divided by v^2, assuming the top line is u and bottom is v

In this function, u= x-3 and v=2x+1

:. u' = 1 " and " v' = 2

So plugging that in gets:

(1*(2x+1)-(x-3)*2)/(2x+1)^2

=((2x+1)-(2x-6))/(4x^2+4x+1)

= (cancel(2x)+1-cancel(2x)+6)/(4x^2-4x+1)

=7/(4x^2-4x+1)