It doesn't matter how you lable your upper and lower bound equations as long as you're consistant. It may be one more step, but I re-write the upper and lower bound equations in terms of U and x before substituting the numerical values. For example, if the equation is U = X^2 + 3X - 1 and the upper limit of X is 9 and the lower limit of X is (-1), I'd write something like: U = X^2 + 3X - 1, X" = 9, X' = (-1)
U' = X'^2 + 3X' - 1 =(-1)^2 + 3(-1) - 1 =1 - 3 - 1 =(-3) Notice how I re-wrote the U = xsomething equation in terms of the upper and lower bounds of U and x instead of writing U (upper/lower bound) = eqn2 even though I knew which X value went with bound? It's one more step but it helps other people to follow what you're doing. It's also easier to find mistakes when it's easy to tell what you're trying to do by looking at the equations.
Re: I need help
U=Xsomething
U'=X'something
U" = X"something
Uupper = Xuppersomethingsomething
Ulower = somethingXlowerXlower*somethingoranother
It doesn't matter how you lable your upper and lower bound equations as long as you're consistant. It may be one more step, but I re-write the upper and lower bound equations in terms of U and x before substituting the numerical values. For example, if the equation is U = X^2 + 3X - 1 and the upper limit of X is 9 and the lower limit of X is (-1), I'd write something like:
U = X^2 + 3X - 1, X" = 9, X' = (-1)
U" = X"^2 + 3X" - 1
= (9)^2 + 3(9) - 1
=81+27-1
=107
U' = X'^2 + 3X' - 1
=(-1)^2 + 3(-1) - 1
=1 - 3 - 1
=(-3)
Notice how I re-wrote the U = xsomething equation in terms of the upper and lower bounds of U and x instead of writing U (upper/lower bound) = eqn2 even though I knew which X value went with bound? It's one more step but it helps other people to follow what you're doing. It's also easier to find mistakes when it's easy to tell what you're trying to do by looking at the equations.