Determine the equation of both lines that are tangent to the graph of y=x^2 +4 and pass through the point (1,-2)

So would I simply use the y=mx+b form, m=2, y= -2, and x = 1?

Printable View

- Mar 21st 2010, 04:43 PMRyGuyFind the equation of both lines?
Determine the equation of both lines that are tangent to the graph of y=x^2 +4 and pass through the point (1,-2)

So would I simply use the y=mx+b form, m=2, y= -2, and x = 1? - Mar 21st 2010, 04:47 PMskeeter
- Mar 21st 2010, 04:50 PMRyGuy
- Mar 21st 2010, 04:57 PMArchie Meade
- Mar 21st 2010, 05:05 PMskeeter
point of tangency on the curve is $\displaystyle (x,x^2+4)

$

each tangent line passes thru the point $\displaystyle (1, -2)$

remember how to find the slope between two points?

... also, note that the slope of both tangent lines is y' = 2x

I'll let you take it from here.