whysoserious
- 2
- 0
Homework Statement
4^x = x^4. My instructor wants me to find the answer that is -0.77, not 2 or 4. And showing work as well.
Solve 4^x = x^4: -0.77 Answer w/Work
- Thread starter whysoserious
- Start date
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
6 replies · 2K views
4^x = x^4. My instructor wants me to find the answer that is -0.77, not 2 or 4. And showing work as well.
Immutef
- 11
- 0
Did you try graphing the equations and finding where they intercept?
Last edited:
- 42,895
- 983
There is no "formula" or elementary function that will solve that. I would try to get it into a form in which I could use Lambert's W function- it is defined as the inverse of [itex]xe^x[/itex].
Axiom17
- 70
- 0
If you detail you calculations so far perhaps then can advice with this 
whysoserious
- 2
- 0
I tried using log but I keep getting stuck at xlog2=2logx
Axiom17
- 70
- 0
Make a quick sketch of the two functions. Just use the range [itex]-2 \leq x \leq 2[/itex] and plot the two lines together. From the graph you should be able to see the intersect and hence the answer you require.
- 42,895
- 983
Why are you ignoring my post? That equation cannot be solved using elementary functions. Do a numerical solution, or graph as Axiom17 and Immutef have suggested, or use Lambert's W function.whysoserious said: