use logarithmic differentiation to find dy/dx y= ((x+2)sqrt(1-x^2))/4x^3

If

then taking the logarithm of both sides and expanding the right side gives

Differentiate both sides with respect to x :

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

what is the question you are asking?