Register to reply

Home school Calculas( high school level)

by Stupid_neko
Tags: calculas, home, school
Share this thread:
Stupid_neko
#1
May6-07, 05:18 PM
P: 3
Hi.. New at this site, hope I'm posting these stuff on the write place....
well i had these question below for review for an exam, hope someone can help me solve them, i did my solution in Paint program and on paper and am linking where i uploaded them, ( image shack)

-Find the second derivative
1)y=2x^3e^4x
solution


2)y=√(x^3+e^-x+5)
** for where 'e^-x' i think the question is wrong,, i think it should be e^x, not sure??
solution


3)Find the second derivative of 'y' with respect to "x" where
y=x^2/X^2
solution


4)Find the equation of 2 lines, each of slope 5, that are tangent to y=x^3+2X

5) Find the asymptotes for
f(x)=x/√(4x-1)

6)A dragster accelerates down a strip adn then brakes, adn comes to stop. Its position function, s(t) is given by s(t)=3t^2-1/5t^3, s'(t) in meters, 't' in seconds
a) when does the dragster come to a stop
b) how far has the dragster traveled.
Solution


7) Find the polynomial with second degree that goes through (1,-1) and whose slope is 1, When x=-1 and where slop is 19, when x=2
solution



8) A helicopter takes off from landing pad at 10:48AM and travels south at 150KM/h is planning to land at 10:56AM.
a) how far is the distance between them changing at 10:50AM( to 2 decimal place)
b) Is the distance between them increasing or decreasing at this instant?


I couldn't answer 4,5,8... please help me with them...and check solution
thank you ...
Phys.Org News Partner Science news on Phys.org
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
turdferguson
#2
May6-07, 07:41 PM
P: 312
For #4, the derivative is a quadratic. There are 2 places where the tan line has a slope of 5. Find the points where it equals 5 (or where that minus 5 equals zero) and then you have 2 points and 2 slopes
Noober
#3
May6-07, 08:21 PM
P: 20
8. If he's traveling at 150 km/h, then that's how fast the distance is changing. For b, it depends. If it went past his destination before 10:50, then the distance is increasing, otherwise it's decreasing.

Stupid_neko
#4
May6-07, 10:23 PM
P: 3
Home school Calculas( high school level)

Quote Quote by turdferguson View Post
For #4, the derivative is a quadratic. There are 2 places where the tan line has a slope of 5. Find the points where it equals 5 (or where that minus 5 equals zero) and then you have 2 points and 2 slopes
For quadratic equation i would need a,b and c. but i have only 2 numbers......and how would i find the point where the point equals 5?


Also can anyone check the solutions i did,

thanks
HallsofIvy
#5
May7-07, 05:40 AM
Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,565
"For quadratic equation i would need a,b and c. but i have only 2 numbers......and how would i find the point where the point equals 5? "
A "point" can't equal 5! You are looking for the value of x such that the derivative 3x2+ 2= 5. Surely you can solve that equation.
sstone
#6
May7-07, 07:38 AM
P: 14
For #1 the final answer(first derivative) is [tex](e^{4x} \cdot 2x^2) \cdot (4x+3)[/tex] not 2x + 3...you multiplyed by 2 insted 4...

Edit...even more simple it is if you leave it like this [tex]6x^2 e^{4x} + 8x^3 e^{4x}[/tex] and make a second derivative...
Stupid_neko
#7
May7-07, 10:42 PM
P: 3
Quote Quote by sstone View Post
Edit...even more simple it is if you leave it like this [tex]6x^2 e^{4x} + 8x^3 e^{4x}[/tex] and make a second derivative...
I factored out the 2x^2, if you factor it back in , you get the same result....So confused,,,dont know where i made mistake sorry sorry,,,,,,,could you show me where i made the mistake,,,

thank you everyone for your help:)
sstone
#8
May10-07, 10:24 AM
P: 14
You multiplied it wrongly...


Register to reply

Related Discussions
High school project to propel a toy rocket as high as possible General Physics 7
Heat of Reaction Experiment, High school level Biology, Chemistry & Other Homework 1
Science Bowls/Competitions for US High School and Middle (Jr High) School Students Academic Guidance 0
No more high school for me! General Discussion 9
High School General Discussion 26