Ask your own question, for FREE!
Mathematics 7 Online
OpenStudy (anonymous):

find the derivative of each of the following

OpenStudy (anonymous):

\[f(x)=\frac{ 6x-11}{ 8x+1 }\]

OpenStudy (anonymous):

@ganeshie8 what would we do in this situation

ganeshie8 (ganeshie8):

familiar wid quotient rule ? or product rule ?

OpenStudy (anonymous):

not really

ganeshie8 (ganeshie8):

you need to knw any one of them to do this

ganeshie8 (ganeshie8):

\(\large \left(\frac{f}{g}\right)' = \frac{g\times f' - g' \times f}{g^2}\)

OpenStudy (anonymous):

i am confused, for f or g whay would we plug in

ganeshie8 (ganeshie8):

\(\large \left(\frac{ 6x-11}{ 8x+1 }\right)' = \frac{(8x+1)\times (6x-11)' - (8x+1)'\times (6x-11)}{(8x+1)^2}\)

OpenStudy (anonymous):

then we multpliy the equations and subtract them

ganeshie8 (ganeshie8):

take the derivatives first

ganeshie8 (ganeshie8):

\(\large \left(\frac{ 6x-11}{ 8x+1 }\right)' = \frac{(8x+1)\times (6x-11)' - (8x+1)'\times (6x-11)}{(8x+1)^2}\) \(\large \left(\frac{ 6x-11}{ 8x+1 }\right)' = \frac{(8x+1)\times (6) - (8)\times (6x-11)}{(8x+1)^2}\)

ganeshie8 (ganeshie8):

now multiply and simplify

OpenStudy (anonymous):

\[\frac{ -82 }{ 80x+1 }\]

OpenStudy (anonymous):

the derivative is 80x which is 80

ganeshie8 (ganeshie8):

?? is this another problem ?

OpenStudy (anonymous):

no isnt that the answer

ganeshie8 (ganeshie8):

nope

ganeshie8 (ganeshie8):

\(\large \left(\frac{ 6x-11}{ 8x+1 }\right)' = \frac{(8x+1)\times (6x-11)' - (8x+1)'\times (6x-11)}{(8x+1)^2}\) \(\large \qquad \qquad ~~= \frac{(8x+1)\times (6) - (8)\times (6x-11)}{(8x+1)^2}\) \(\large \qquad \qquad ~~= \frac{48x+6 - 48x +88}{(8x+1)^2}\)

ganeshie8 (ganeshie8):

simplify

OpenStudy (anonymous):

@ganeshie8 it would become \[\frac{ 94 }{ (8x-1)^2 }\]

ganeshie8 (ganeshie8):

how come denominator changed to 8x-1 ha ?

ganeshie8 (ganeshie8):

it should be (8x+1)^2 in the denominator right ?

OpenStudy (anonymous):

@ganeshie8 my mistake, but that would correct though\[\frac{ 94 }{ 8x+1 }^2\]

OpenStudy (anonymous):

power of two is for denominator

ganeshie8 (ganeshie8):

\(\large \frac{94}{(8x+1)^2}\) is \(\large \color{Red}{\checkmark}\)

OpenStudy (anonymous):

but would the derivative be 8

ganeshie8 (ganeshie8):

derivative is \(\large \frac{94}{(8x+1)^2} \)

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!