PreCal
posted by Mike on .
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)

I'll do one of them. Use the same method for the other.
17) y = x^2/2 and the slope of the parabola is dy/dx = x
When x = 3, y = 9/2 and the slope is 3. A straight line going through (3, 9/2) with slope 3 has the equation
y  9/2 = 3[x (3)]
y = 3x + 9/2 9 = 3x 9/2
The x intercept (where y = 0) is
x = 3/2