Thursday

January 29, 2015

January 29, 2015

Posted by **Steff** on Wednesday, June 15, 2011 at 8:26am.

f(t)=(4+√t)(4t^2-5)

This is what I have so far...

(4+√t)(8t)+(4t^2-5) (1/2t^-1/2)

Am struggling to get this in factored form. Am working on a multiple choice take home test and nothing I am getting matches.

- derivative calculus -
**Jai**, Wednesday, June 15, 2011 at 8:40amthe derivative you got is correct.

by distributing, we can further simplify this into:

32t + 8t^(3/2) + 2t^(3/2) - (5/2)t^(-1/2)

10t^(3/2) + 32t - (5/2)t^(-1/2)

hope this helps~ :)

- derivative calculus -
**Reiny**, Wednesday, June 15, 2011 at 8:42amsofar ok

why don't we expand this ... and simplify to get

32t + 10t^(3/2) - (5/2)t^(-1/2)

= 32t + 10t√t - 5/(2√t)

Since I don't know what your choices are, I don't know in which direction to go from here.

Here is a good trick to see if your answer is the same as theirs.

Pick any point on the original

e.g. let t = 1

f(1) = 5(4-5) = -5

so (1,-5)

so sub in t = 1 into our derivative answer to get

32(1) + 10(1)(1) - 5/(2(1)) = 39.5

Any of the choices not giving you 39.5 would be incorrect.

- derivative calculus -
**Steff**, Wednesday, June 15, 2011 at 8:50amHere are my options

a) 10t^2+32t√t - 5 / √t

b) 20t^2-64t√t - 5 / 2√t

c) 20t^2+ 32t√t - 5 / 2√t

d) 20t^2+64t√t - 5 / 2√t

e) 10t^2-32t√t - 5 / √t

- Multiple choice options -
**Steff**, Wednesday, June 15, 2011 at 9:11amadded

- derivative calculus -
**Reiny**, Wednesday, June 15, 2011 at 10:22amIf c) is written as

(20t^2 + 32t√t - 5)/(2√t) it would be same as my answer.

The formed a common denominator

the way you typed it, only the -5 would be divided by 2√t

- derivative calculus -
**Steff**, Wednesday, June 15, 2011 at 10:31amThanks. I see my mistake now.

**Answer this Question**

**Related Questions**

Math - Find an equation of the line that bisects the obtuse angles formed by the...

Math(I Don't Get THIS!!) - 15sqrt8x^16/5sqrt2x^4 *I totally need help with this ...

Algebra - Simplify the expressions and solve the equations 1. 2√3 - √...

Math help Ms. Sue please - 1. What is the simplified form of the expression? 7m^...

Algebra - How would i complete these problems? 1. (√6mn)^5 2. ^3√16x...

maths - I will be thankfull to you if you help me to solve the below problem: 6...

algebra 1 - alright i have a few questions if its ok..? Simplify: 1. -2√(...

Calculus - y=(√x)/((√x)+1) Find the concavity and point of ...

Algebra Work Check - 1. 5√6 * 1/6√216 5/6 * √1296 5/6 * √...

Algebra 2 Answer Check - Simplify by rationalizing each denominator. 1. 2/√...