How do you find the derivative of y= [(2x+3)/(x-2)][(5x-1)/(3x-2)] using the chain rule?

1 Answer

y'=(-119x^2+98x+28)/(3x^2-8x+4)^2

Explanation:

From the given equation.

y=[(2x+3)/(x-2)][(5x-1)/(3x-2)]

Simplify the right side of the equation by multiplying the rational expressions first

y=[(2x+3)/(x-2)][(5x-1)/(3x-2)]

y=[(10x^2+13x-3)/(3x^2-8x+4)]

Find the derivative by using the formula d/dx(u/v)=(v*d/dx(u)-u*d/dx(v))/v^2

Let u=10x^2+13x-3

Let v=3x^2-8x+4

Use now the formula

d/dx(u/v)=(v*d/dx(u)-u*d/dx(v))/v^2

y'=d/dx((10x^2+13x-3)/(3x^2-8x+4))

y'=((3x^2-8x+4)*d/dx(10x^2+13x-3)-(10x^2+13x-3)*d/dx(3x^2-8x+4))/(3x^2-8x+4)^2

y'=((3x^2-8x+4)*(20x+13)-(10x^2+13x-3)(6x-8))/(3x^2-8x+4)^2

Simplify the numerator

y'=(60x^3-160x^2+80x+39x^2-104x+52-(60x^3+78x^2-18x-80x^2-104x+24))/(3x^2-8x+4)^2

y'=(60x^3-160x^2+80x+39x^2-104x+52-60x^3-78x^2+18x+80x^2+104x-24)/(3x^2-8x+4)^2

y'=(-119x^2+98x+28)/(3x^2-8x+4)^2

God bless....I hope the explanation is useful.