μ_x = E[X] =		^∞	xf_x(x)dx
		_{– ∞}

=		¹	x.3(1 – x) ²dx
		₀

= 3		¹	(x – 2x² + x³)dx
		₀

= 3		x²	-	2x³	+	x⁴		¹
		2		3		4		₀

= 3		1	-	2	+	1
		2		3		4

= 3		6 - 8 + 3		=	1
		12			4

f_x(x) =		3(1 – x)²; for 0 ≤ x ≤ 1
		0; otherwise