In a uniform gravitational field `g`, which is acting vertically downward, a ball is thrown at an angle with horizontal such that the initial (immediately after projection) radius of curvature is `8` times the minimum radius of curvature. If angle of projection is `theta`, then find the value of `theta`.

Explanation

To solve the problem, we need to find the angle of projection \( \theta \) given that the initial radius of curvature \( R \) is 8 times the minimum radius of curvature \( R_{min} \).

### Step 1: Understand the concept of radius of curvature
The radius of curvature \( R \) of a projectile at any point in its trajectory is given by the formula:
\[ R = \frac{(v^2)}{g \cos \theta} \]
where \( v \) is the velocity of the projectile at that point, \( g \) is the acceleration due to gravity, and \( \theta \) is the angle of projection.
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