Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
what's up guys!? so look at this, where did (-x) go in this equation? It says a^2; is this a typo?
aiight, thanks for reading my question. keep it locked g.
2 Answers
- 3 years agoFavorite Answer
It is because of the 1 in the equation. The 1 was replaced with (a^2 - x^2)/(a^2 - x^2) and then added to the rest of the stuff underneath the radical. Since the (-x) is squared the numerator can be simplified: a^2 - x^2 + x^2 = a^2
No typo.
Hope this makes sense.
- icemanLv 73 years ago
f(x) = √(a^2 - x^2)
f'(x) = -x/√(a^2 - x^2)
f'(x)^2 = x^2/(a^2 - x^2)
1 + f'(x)^2 = 1 + x^2/(a^2 - x^2) = (a^2 - x^2 + x^2]/(a^2 - x^2) = a^2/(a^2 - x^2)
√(1 + f'(x)^2) = √[(a^2) /(a^2 - x^2)] => you have this, if simplified further:
= √(a^2) /√(a^2 - x^2) = a/√(a^2 - x^2)
