thanks for the response, i corrected the formatting. the formula is very helpful.
is there any reason my steps don't work? it seems like I'm applying all the basic principles correctly, so i feel stumped.
find the total derivative dz/dt, given:
z=(x^2)-8xy-(y^3) where x=3t and y=1-t
my steps look like this, can someone point out where i am going wrong, please?
z'=2x-8(x'y+y'x)-3y^2 where
x'=3 and y'=-1
2(3t)-8[3(1-t)+(-1)(3t)]-3(1-t)^2
=6t-8[3-3t+(-3t)]-3(1-2t+t^2)
=6t-8(3-6t)-3(1-2t+t^2)...