A linguist studying language evolution uses computational models to analyze the frequency of word usage, modeled by the equation \( f(x) = a \sin(bx + c) + d \). If \( f(0) = 2 \), \( f(\frac\pi2b) = 4 \), and the average value of the function over one period is 3, find the constants \( a \), \( b \), \( c \), and \( d \). - Portal da Acústica