# Pre-Calculus

posted by .

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

• Pre-Calculus -

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
(y-8) = 4(x-4)
Rewrite that in standard y = mx + b form.

• Pre-Calculus -

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

## Similar Questions

1. ### 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). …
2. ### Pre-Cal

Find an equation of the tangent line to the parabola at the given point, and find the x-intercept of the line. 17) x^2=2y , (-3,9/2) 18) y=-2x^2 , (-1,-2)
3. ### MATH

I had an assignment containing 45 problems, and I am unsure of 4, can you check and see if the answers are correct?
4. ### Math

I had an assignment containing 45 problems, and I am unsure of 4, can you check and see if the answers are correct?
5. ### Math

I had an assignment containing 45 problems, and I am unsure of 4, can you check and see if the answers are correct?
6. ### math

i have more than one question so if u no any of the answers please tell me 1.) write the point-slope form of the equation of the line with slope -2 passing through the point ( -5, -9). 2.) write the point-slope form of an equation …
7. ### Algebra

graph the equation x-3=y (where do I plot the points?
8. ### 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 …
9. ### Calculus AB

Could someone please help me with these tangent line problems?
10. ### Business Math

a) Given x + y = 2 and y = x² - x - 2, find the x-intercepts and y-intercept 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 …

More Similar Questions