PreCalculus
posted by Shirley .
Im having trouble with this.
Find an equation of the tangent line to the parabola at the given point and find the xintercept of the line.
x^2=2y (4,8)

PreCalculus 
drwls
y = (1/2) x^2
The slope of the curve is dy/dx = x
At x = 4, the slope is 4.
For a line though (4,8) with slope = 4, the equation is
(y8) = 4(x4)
Rewrite that in standard y = mx + b form. 
PreCalculus 
GanonTEK
well, from the above equation y = (x^2)/2
to get an equation of a line you need a slope and a point. You have a point and to get the slope we need to get dy/dx
and sub in the value for x in the point given [in this example 4]
Then sub your point (x1,y1) and the slope (m) into
y  y1 = m(x  x1)
and then just tidy up
Hope that helps
Respond to this Question
Similar Questions

Calculus
I have a two part question that pertains to a curve (r(x)) and its tangent line at x=3. We are given that at x=3, r(x)=8. In order to find the slope of the tangent line, we are given another point (on the tangent line): (3.2, 8.5). … 
PreCal
Find an equation of the tangent line to the parabola at the given point, and find the xintercept of the line. 17) x^2=2y , (3,9/2) 18) y=2x^2 , (1,2) 
MATH
I had an assignment containing 45 problems, and I am unsure of 4, can you check and see if the answers are correct? 
Math
I had an assignment containing 45 problems, and I am unsure of 4, can you check and see if the answers are correct? 
Math
I had an assignment containing 45 problems, and I am unsure of 4, can you check and see if the answers are correct? 
math
i have more than one question so if u no any of the answers please tell me 1.) write the pointslope form of the equation of the line with slope 2 passing through the point ( 5, 9). 2.) write the pointslope form of an equation … 
Algebra
graph the equation x3=y (where do I plot the points? 
calculus
5. Let f be the function given by f(x) = x3 7x + 6. a. Find the zeros of f b. Write an equation of the line tangent to the graph of f at x = 1 c. Find the x coordinate of the point where the tangent line is parallel to the secant … 
Calculus AB
Could someone please help me with these tangent line problems? 
Business Math
a) Given x + y = 2 and y = x²  x  2, find the xintercepts and yintercept of the parabola. b) Find the turning point of the parabola. c) Find the x intercept and y intercept of the line graph. d) Find the point(s) of intersection …