Expert: Paul Klarreich - 5/27/2008

Question
Looking at your solution to the following question:
Subject:  Calculus
Question:  Could you help me with this?  Graph the two parabolas y=x^2 and y=-x^2+2x-5 in the same coordinate plane. Find the equations of the two lines simultaneously tangent to both parabolas.

In the part where you do the following simplifaction

Simplify the other:
2a = -2b + 1
a = -b + 1 = 1 - b

Shouldn't the 1 become 0.5? Other than that thanks for the Solution it looks very nice, much nicer than my derivation I tried earlier with coupled quadratics.

Answer
Questioner:   Iain
Category:  Calculus
Private:  No
 
Subject:  Review of tangent line answer
Question:  Looking at your solution to the following question:
Subject:  Calculus
Question:  Could you help me with this?  Graph the two parabolas y=x^2 and y=-x^2+2x-5 in the same coordinate plane. Find the equations of the two lines simultaneously tangent to both parabolas.

In the part where you do the following simplifaction

Simplify the other:
2a = -2b + 1
a = -b + 1 = 1 - b

Shouldn't the 1 become 0.5? Other than that thanks for the Solution it looks very nice, much nicer than my derivation I tried earlier with coupled quadratics.
......................................................
Hi, Iain,

Thank you. It doth appear that I have made a boo-boo.  Could you send me the link to the question -- it was probably some time ago, but I remember doing this.  Then I can post a correction.