Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
find an equation of the normal line to the parabola y=x^28x+9 at point (3,6)... help me..
 one year ago
 one year ago
find an equation of the normal line to the parabola y=x^28x+9 at point (3,6)... help me..
 one year ago
 one year ago

This Question is Closed

LogicalAppleBest ResponseYou've already chosen the best response.2
Can you use calculus?
 one year ago

sha0403Best ResponseYou've already chosen the best response.0
how to use it? i don't know coz it do not give the value of x after differetiate.. so i don't know how to find m..
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
What do you get for y'(x) in general?
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
Perfect. This is the equation of the tangents of x^2  8x + 9. Let x = 3 and solve for y'(x) to get the tangent at that point.
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
More specifically, y'(x) gives you the 'slope' of the tangent at x.
 one year ago

sha0403Best ResponseYou've already chosen the best response.0
so after that if i get the value of m,, should i substitute the (3,6) again tu find c?
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
Let's assume you found the slope at x = 3. This is the slope of the tangent line. The slope of the normal line would be perpendicular to it. What is the relationship of slopes between perpendicular lines?
 one year ago

sha0403Best ResponseYou've already chosen the best response.0
so, it share the same value of x? right?
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
Well, the point (3, 6) will be the same. The only difference is, the slope of the normal line will be the negative reciprocal of the slope of the tangent line (since they are perpendicular).
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
dw:1356835091005:dw
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
The point there is supposed to represent (3, 6). The tangent line is drawn with a slope of m = y'(3), and the normal line is also drawn perpendicular to it.
 one year ago

sha0403Best ResponseYou've already chosen the best response.0
ok i understand now...thanks for your explanation....
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
y'(3) = 2(3)  8 = 2 = slope of the tangent line Thus the slope of the normal line would be 1/2 and pass through (3, 6).
 one year ago

sha0403Best ResponseYou've already chosen the best response.0
but i little bit confuse,, how do u know the shape of graph was perpendicular?
 one year ago

LogicalAppleBest ResponseYou've already chosen the best response.2
Do you mean the direction of the normal line? A normal line is just a line perpendicular to whatever shape we're talking about. More specifically, a normal line is perpendicular to a tangent line.
 one year ago

sha0403Best ResponseYou've already chosen the best response.0
ok i understand..thank u,, :)
 one year ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.