# Quick Calc help

**URL:** <https://forums.speedlife.net/t/quick-calc-help/71117>\
**Category:** NYSpeed Off Topic\
**Created:** [July 26, 2009, 12:43pm UTC](https://forums.speedlife.net/t/quick-calc-help/71117 "2009-07-26T12:43:02Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Toda\_Party](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/toda_party/32/7354_2.png) [@Toda\_Party](https://forums.speedlife.net/u/Toda_Party)\
**Post date:** [July 26, 2009, 12:43pm UTC](https://forums.speedlife.net/t/quick-calc-help/71117/1 "2009-07-26T12:43:02Z")

</div>

My teacher gave us an answer sheet but I’m suspecting its wrong…

f(x) = (x^2-x)/(4x)

using quotient rule isn’t it

[(4x) x (2x-1)] - [(x^2-x) x (4)] / (4x)^2 then solve out?

he’s giving us the deriv of (x^2-x) as 2x on the answer sheet…shouldn’t it be 2x-1??

---

<div class="post-metadata">

**Author:** ![ILC](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilc/32/5337_2.png) [@ILC](https://forums.speedlife.net/u/ILC)\
**Post date:** [July 26, 2009, 12:47pm UTC](https://forums.speedlife.net/t/quick-calc-help/71117/2 "2009-07-26T12:47:25Z")

</div>

ugh its been a while one second.

I hate the quotient rule.

first just simplify it though. to (x-1)/3 then try it again.

OH! i just reread your question and yes… the derive of x^2-x = 2x-1

---

<div class="post-metadata">

**Author:** ![ILC](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilc/32/5337_2.png) [@ILC](https://forums.speedlife.net/u/ILC)\
**Post date:** [July 26, 2009, 12:58pm UTC](https://forums.speedlife.net/t/quick-calc-help/71117/3 "2009-07-26T12:58:21Z")

</div>

answer is 1/4th? for some reason i get 1/3 when i reduce it, I’m probably mixing up the rules since its been FOREVER lol

---

<div class="post-metadata">

**Author:** ![Toda\_Party](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/toda_party/32/7354_2.png) [@Toda\_Party](https://forums.speedlife.net/u/Toda_Party)\
**Post date:** [July 26, 2009, 1:25pm UTC](https://forums.speedlife.net/t/quick-calc-help/71117/4 "2009-07-26T13:25:58Z")

</div>

yeah the answer is 1/4 supposedly, i was just confused on how he got the der of x2-x as 2x. damn sloppy answer key.

thanks brah