Please help solve the equation in black hole f(R) theories

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SUMMARY

The discussion centers on solving equations in black hole f(R) theories, specifically referencing the paper available at https://arxiv.org/abs/1210.4699. The user reports discrepancies between their results and those presented in the paper, particularly at zero order. Key variables involved include E, H, b, R, and Φ, with the equation involving derivatives and specific terms that may contain errors. The user is advised to verify inputs, derivatives, and potential missing terms or sign errors in their calculations.

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  • Understanding of f(R) gravity theories
  • Familiarity with differential equations and their applications in theoretical physics
  • Knowledge of tensor calculus and general relativity
  • Proficiency in mathematical notation and manipulation of equations
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  • Review the paper "How to solve this equation?" at https://arxiv.org/abs/1210.4699 for foundational concepts
  • Learn about the implications of zero-order approximations in f(R) theories
  • Investigate common errors in solving differential equations in theoretical physics
  • Consult advanced texts on black hole physics and f(R) gravity for deeper insights
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The discussion is beneficial for theoretical physicists, researchers in gravitational theories, and graduate students studying black hole dynamics and f(R) gravity models.

Boy_saber
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In the paper https://arxiv.org/abs/1210.4699. How to solve this equation?

1.jpg


I've tried it, it's not same as in this paper. Even zero order still not the same.
This is what I try to do at zero order.

input

$$E=E_0\left(r_0\right)$$
$$H=H_0\left(r_0\right)$$
$$b=b\left(r_0\right)$$
$$R=R_0\left(r_0\right)$$
$$\Phi =\Phi _0\left(r_0\right)$$
$$r=r_0$$
$$g^{11}=1-\frac{b}{r}$$
$$\Box f_R=H g^{11} \left(\frac{\partial R}{\partial r_0}\right){}^2+E \left(\left(1-\frac{b}{r}\right) \left(\frac{\partial R}{\partial r_0} \left(-\frac{\partial \Phi }{\partial r_0}\right)+\frac{\frac{\partial R}{\partial r_0}}{r}+\frac{\partial }{\partial r_0}\frac{\partial R}{\partial r_0}\right)+\frac{\left(1-\frac{\partial b}{\partial r_0}\right) \frac{\partial R}{\partial r_0}}{r}\right)$$

output

$$-\frac{b\left(r_0\right) H_0\left(r_0\right) R_0'\left(r_0\right){}^2}{r_0}+\frac{b\left(r_0\right) E_0\left(r_0\right) R_0'\left(r_0\right) \Phi _0'\left(r_0\right)}{r_0}-\frac{E_0\left(r_0\right) b_0'\left(r_0\right) R_0'\left(r_0\right)}{r_0}-\frac{b\left(r_0\right) E_0\left(r_0\right) R_0'\left(r_0\right)}{r_0^2}-\frac{b\left(r_0\right) E_0\left(r_0\right) R_0''\left(r_0\right)}{r_0}+H_0\left(r_0\right) R_0'\left(r_0\right){}^2-E_0\left(r_0\right) R_0'\left(r_0\right) \Phi _0'\left(r_0\right)+\frac{2 E_0\left(r_0\right) R_0'\left(r_0\right)}{r_0}+E_0\left(r_0\right) R_0''\left(r_0\right)$$

Where did I make a mistake?
 
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It is difficult to pinpoint the exact mistake without more context and information about the specific equation and problem being solved. However, it is possible that there may be a missing term or a sign error in the output equation. It is also important to carefully check all the inputs and their derivatives to ensure they are correct. It may also be helpful to consult with a colleague or a subject expert for further assistance in solving the equation.
 

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