Find the dy/dx for y=x^2(x+2)^4
First I want to show you my calculation :
Let u = x^2, so du/dx = 2x
Let v = (x+2)^4, so dv/dx = 4(x+2)^3
dy/dx = x^2 [4(x+2)^3] + (x+2)^4 (2x)
= 4x^2 (x+2)^3 + 2x (x+2)^4
Okay, so the answer is 2x(x+2)^3(3x+2)
How can I get 2x(x+2)^3(3x+2) from 4x^2 (x+2)^3 + 2x (x+2)^4 ?
Explain please, so that I can solve this question ! Thanks. :)
First I want to show you my calculation :
Let u = x^2, so du/dx = 2x
Let v = (x+2)^4, so dv/dx = 4(x+2)^3
dy/dx = x^2 [4(x+2)^3] + (x+2)^4 (2x)
= 4x^2 (x+2)^3 + 2x (x+2)^4
Okay, so the answer is 2x(x+2)^3(3x+2)
How can I get 2x(x+2)^3(3x+2) from 4x^2 (x+2)^3 + 2x (x+2)^4 ?
Explain please, so that I can solve this question ! Thanks. :)
-
you can just apply product rule here...
y=x^2(x+2)^4
take derv of first term multiplied by second term
2x(x+2)^4
then add the derv of second term multiplied by first term
2x(x+2)^4 + 4x^2(x+2)^3
Then factor out the (x+2)^3 from both and group what remains.
(x+2)^3 (2x(x+2) + 4x^2))
simplify
(x+2)^3 (2x^2 + 4x + 4x^2)
(x+2)^3 (6x^2 + 4x)
then factor out 2x WITHIN THE SECOND TERM ALONE.
(x+2)^3 * 2x * (3x^2 + 2x)
leaving
2x(3x + 2)(x+2)^3
y=x^2(x+2)^4
take derv of first term multiplied by second term
2x(x+2)^4
then add the derv of second term multiplied by first term
2x(x+2)^4 + 4x^2(x+2)^3
Then factor out the (x+2)^3 from both and group what remains.
(x+2)^3 (2x(x+2) + 4x^2))
simplify
(x+2)^3 (2x^2 + 4x + 4x^2)
(x+2)^3 (6x^2 + 4x)
then factor out 2x WITHIN THE SECOND TERM ALONE.
(x+2)^3 * 2x * (3x^2 + 2x)
leaving
2x(3x + 2)(x+2)^3
-
4x^2 (x+2)^3 + 2x (x+2)^4 = 2x(x+2)^3 [2x + x + 2] = 2x(x+2)^3(3x+2)
-----------
Ideas: GCF = 2x(x+2)^3
-----------
Ideas: GCF = 2x(x+2)^3