Linear Approximation in Two Variables Example 5 PART 1/2 (KristaKingMath)

Linear Approximation in Two Variables calculus example.

● ● ● GET EXTRA HELP ● ● ●

● ● ● CONNECT WITH KRISTA ● ● ●

Hi, I’m Krista! I make math courses to keep you from banging your head against the wall. ;)

Math class was always so frustrating for me. I’d go to a class, spend hours on homework, and three days later have an “Ah-ha!” moment about how the problems worked that could have slashed my homework time in half. I’d think, “WHY didn’t my teacher just tell me this in the first place?!”

[kristakingmath]

It's because you're using Chain Rule to take the derivative. When you use Chain Rule, you take the derivative of the outside function, leaving the inside function completely untouched, then you multiply by the derivative of the inside function. That denominator is the inside function that was left untouched (unchanged). Hope that helps!! :)