Question

Find the curvature of y=x^3+1.

Answer 1

@satellite73 @thomaster @ganeshie8 @iambatman @mathstudent55 @freckles @perl @e.mccormick

Answer 2

http://tutorial.math.lamar.edu/Classes/CalcIII/Curvature.aspx
Ooughh, Calc III

Answer 3

\[k(x)=\frac{ \left| y'' \right| }{ [1+(y')^2]^{3/2} }\]

Answer 4

I know that y'=3x^2 and y"=6x. So I got\[k(x)=\frac{ 6x }{ (1+9x^4)^{3/2} }\]

Answer 5

But the answer in the book is\[\frac{ 6\left| x \right| }{ (1+9x^4)^{3/2} }\]

Answer 6

I don't know which answer is right. @ganeshie8 @thomaster

Answer 7

How did you get your answer to be out of the | |?

Answer 8

So the book's answer is right?

Answer 9

Well, look a the formula you posted. There are tules for dealing with | |. They don't change for calculus...

Answer 10

rules that is...

Answer 11

So the book's answer must be right then, is that correct?

Answer 12

If that formula is correct, yes. Because you can't just take a variable outside of absolute value.

Answer 13

Okay, thank you!