-8.2.59 Find eq for level surface

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Discussion Overview

The discussion revolves around finding an equation for the level surface of the function \( f(x,y,z) = x + e^{y+z} \) that passes through the point \( (1, \ln(4), \ln(9)) \). The focus is on the mathematical reasoning involved in determining this level surface equation.

Discussion Character

  • Mathematical reasoning

Main Points Raised

  • One participant suggests that to find the level surface, one should set \( f(x,y,z) = f(1, \ln(4), \ln(9)) \).
  • Another participant calculates \( f(1, \ln(4), \ln(9)) \) and finds it to be \( 37 \), indicating that the level surface equation would be \( x + e^{y+z} = 37 \).
  • There is repetition in the approach and calculations presented by participants, reinforcing the method of evaluating the function at the specified point.

Areas of Agreement / Disagreement

Participants appear to agree on the method of finding the level surface and the resulting equation, as the same calculations and conclusions are reiterated without challenge.

Contextual Notes

The discussion does not address any potential limitations or assumptions in the calculations or the definitions of the function and level surface.

Who May Find This Useful

Readers interested in mathematical reasoning related to level surfaces and function evaluations may find this discussion relevant.

karush
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$\tiny{x4.01}$
$\textsf{Find an equation for the level surface of the function}$
$$f(x,y,z)=x+e^{y+z}$$
$\textsf{ that passes through the point}$
$$(1, \ln(4), \ln(9))$$
 
Last edited:
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Basically, you want:

$$f(x,y,z)=f\left(1,\ln(4),\ln(9)\right)$$

So, what do you get?
 
MarkFL said:
Basically, you want:

$$f(x,y,z)=f\left(1,\ln(4),\ln(9)\right)$$

So, what do you get?

plug in would be

$f(1,\ln(4),\ln(9))=1+e^{\ln(4)+\ln(9)}=1+4 \cdot 9 =37$
 
Last edited:
karush said:
plug in would be

$f(1,\ln(4),\ln(9))=1+e^{\ln(4)+\ln(9)}=1+4 \cdot 9 =37$

Yes, so the equation of the level surface would be:

$$x+e^{y+z}=37$$
 

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