Given that $$ds² = c²dt² - A(r)dr² - r²(d \theta ² + sin²({\theta})d \phi ²).$$$$ds² = c²dt² - A(r)dr² - r²(d \theta ² + \sin²({\theta})d \phi ²).$$ I can easily find the metric for this particular situation. But the question is: how do you find the Ricci scalar for this given metric?
Intuitively I would think the Ricci scalar is zero (like in the Schwarzschild Metric), but I'm not even sure if this is correct. I think there should be a really easy way to calculate this, but all I can find is writing the Ricci tensor with Christoffel symbols. But writing this out seems very long... Any ideas?