Posted by Shirley on Sunday, March 22, 2009 at 6:21pm.
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, Sunday, March 22, 2009 at 7:34pm
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, Sunday, March 22, 2009 at 7:35pm
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
Answer This Question
Related Questions
 PreCal  Find an equation of the tangent line to the parabola at the given ...
 Algebra  graph the equation x3=y (where do I plot the points?) find the ...
 math  i have more than one question so if u no any of the answers please tell ...
 Calculus AB  Could someone please help me with these tangent line problems? 1) ...
 Calculus  I have a two part question that pertains to a curve (r(x)) and its ...
 Math  I had an assignment containing 45 problems, and I am unsure of 4, can you...
 Math  I had an assignment containing 45 problems, and I am unsure of 4, can you...
 MATH  I had an assignment containing 45 problems, and I am unsure of 4, can you...
 calculus  5. Let f be the function given by f(x) = x3 7x + 6. a. Find the ...
 Calculus AB  Sorry but I've got a lot of problems that I don't understand. 1) ...
More Related Questions