\[ \int \frac{dx}{\cos x \, (1 + \cos x)} = \; ? \]
The approximate value of
\[ \frac{1}{(2.002)^2} \]
is ______.
The derivative of
\[ y = \sqrt{\sin x + \sqrt{\sin x + \sqrt{\sin x + \cdots \infty}}} \]
The value of
\[ {}^{47}C_{4} + \sum_{j=1}^{5} {}^{(52-j)}C_{3} \]
If \( X \sim B(35, p) \) such that \( 7P(X = 0) = P(X = 1) \), then the value of
\[ \frac{P(X = 15)}{P(X = 20)} \]