Thread: Implicit differentiation

Hi,

I have the following equation:

ln(8y)+6xy=ln(sin(4x))

After differentiating I get:

(1/8y)(dy/dx)+6y+6x*(dy/dx)=(4cos(4x))/sin(4x)

And with this, I need to work out dy/dx at (0,0)

When I try this it seems messy and I get zero. Can someone explain where I have gone wrong please

Many thanks

Originally Posted by Bryn

Hi,

I have the following equation:

ln(8y)+6xy=ln(sin(4x))

After differentiating I get:

(1/8y)(dy/dx)+6y+6x*(dy/dx)=(4cos(4x))/sin(4x)

And with this, I need to work out dy/dx at (0,0)

When I try this it seems messy and I get zero. Can someone explain where I have gone wrong please

Many thanks

Dear Bryn,

Note that the equation, is not defined when y=o since ln(0) is not defined. Therefore you cannot find at (0,0)

Hope this will help you.