The differential equation \( x^2 f'(x) = 2f(x) + 3 \) with the initial condition \( f(1) = 4 \) is provided. To find \( f(x) \), the equation is first rewritten as \( f'(x) = \frac{2f(x) + 3}{x^2} \) by dividing both sides by \( x^2 \). This first-order linear differential equation is solved using integrating factors. Subsequently, \( x = 2 \) is substituted, and \( 2f(2) \) is calculated.
Final Answer: \( 2f(2) = 29 \).
If the mean and the variance of the data 
are $\mu$ and 19 respectively, then the value of $\lambda + \mu$ is
In the figure, a sector of the circle with central angle 120° is given. If a dot is put in the circle without looking, what is the probability that the dot is in the shaded region ?