대답:
# 2x ^ 2cos (3x) + (4xsin (3x)) / 3+ (4cos (3x)) / 9 + C #
설명:
먼저, 배제하자. #6# 우리를 떠나야 해. # intx ^ 2sin (3x) dx #
부품 별 통합: # intvu '= uv-intuv'#
# u '= sin (3x), u = -cos (3x) / 3 #
# v = x ^ 2, v '= 2x #
# 6 (- (x ^ 2cos (3x)) / 3 + 2 / 3intxcos (3x) dx) #
# u '= cos (3x), u = sin (3x) / 3 #
# v = x, v '= 1 #
# 3 (- (x ^ 2cos (3x)) / 3 + 2 / 3 ((xsin (3x)) / 3- intsin (3x) / 3dx)) #
(3x) / 3 + cos (3x) / 9)) # 6 (- (x ^ 2cos (3x)) / 3 + 2 / 3)
# 2x ^ 2cos (3x) + (4xsin (3x)) / 3+ (4cos (3x)) / 9 + C #
