• Coming soon...a Bored of Studies school holiday event for 2020 HSC students
    Watch this space!
  • Looking for HSC notes and resources?
    Check out our Notes & Resources page

MATH HELP!! (1 Viewer)

jasminerulez

Active Member
Joined
Feb 21, 2013
Messages
109
Gender
Undisclosed
HSC
N/A
I'm struggling with this past paper question, some help will be appreciated!!

Find the equation of the line when f''(x) = 18x+4 and when x= -1, f(x)=0 and also when x=1, y=10

THANK YOU!!
 
Last edited:

Pedro123

Member
Joined
Jun 17, 2019
Messages
92
Gender
Male
HSC
2021
What past paper is it for? (Year, School)
From what I see, this must be referring to 2 separate questions (Because there is no line with that derivative that satisfies both conditions you put up)

As such, what you do is you integrate 18x + 4. This then gives you some primitive function with a +c at the end of it. Then, you sub in the values of x and f(x) into the equation, and solve it for c (So if the equation was 3x+c=y, sub in a value for x and y and then solve for c). Do this for both points to find your answers (Since there have to be 2).
 
Joined
Oct 19, 2019
Messages
20
Gender
Male
HSC
2020
You would integrate the 18x+4 equation to get dy/dx=9x^2+4x+c, and sub in x=-1, dy/dx=0 to find the value of c. You now have your dy/dx equation and just do the same thing but with values x=1, y=10 to find the equation of the curve.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top