Question

calculate dy/dx. You need not expand your answer.

y = (9x^2 + x)(x − x^2)

Answer 1

i used the product rule, its jsut getting all over the place

Answer 2

by product rule,
dy/dx = d(9x^2 + x)(x − x^2)+ (9x^2 + x)d(x − x^2)
= (18x+1)(x-x^2) + (9x^2 +x)(1-2x)

Answer 3

\[(9x^2 + x)(x-2x)+(18x+1)(x-x^2)\]

Answer 4

and u can leave it at that

Answer 5

so \[9x^3-18x^3+x^2-2x^2+18x^2-18x^3+1x-x^2\]?

Answer 6

****need not expand your answer????

Answer 7

Exapnd is to get
\[(9x^2 + x)(x − x^2)=-9 x^4+8 x^3+x^2

\]
and differentiate after.

Answer 8

umm, im confused as to what you just said

Answer 9

it should be \[\large(9x^2 + x)(1-2x)+(18x+1)(x-x^2)\]

Answer 10

you wrote x-2x instead

Answer 11

i understand, i am just having trouble solving that whole equation

Answer 12

so ill try yours out right now

Answer 13

so is it \[26x^2 - 48x^3 +2x \]

Answer 14

which is \[-48x^3 + 26x^2 + 2x\]

???

Answer 15

you don't need to ....the question says no need to expand...

but if you do you should get\(-36x^3+24x^2+2x\)

Answer 16

got it

Answer 17

which is the same as if you differentiate \(y=-9 x^4+8 x^3+x^2\) as eliassaab suggested

Answer 18

Without expansion
\[(18 x+1)
\left(x-x^2\right)+(1-2 x)
\left(9 x^2+x\right)
\]