integral of (e^(3x)sin(4x))
please show all steps :)
please show all steps :)
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Integrate by parts...twice
int(u * dv) = u * v - int(v * du)
u = e^(3x)
du = 3 * e^(3x) * dx
dv = sin(4x) * dx
v = (-1/4) * cos(4x)
int(e^(3x) * sin(4x) * dx) = (-1/4) * e^(3x) * cos(4x) - int((-1/4) * 3 * e^(3x) * cos(4x) * dx)
int(e^(3x) * sin(4x) * dx) = (-1/4) * e^(3x) * cos(4x) + (3/4) * int(e^(3x) * cos(4x) * dx)
u = e^(3x)
du = 3 * e^(3x) * dx
dv = cos(4x) * dx
v = (1/4) * sin(4x)
int(e^(3x) * sin(4x) * dx) = (-1/4) * e^(3x) * cos(4x) + (3/4) * ((1/4) * e^(3x) * sin(4x) - int((3/4) * e^(3x) * sin(4x) * dx))
Let int(e^(3x) * sin(4x) * dx) = t
t = (-1/4) * e^(3x) * cos(4x) + (3/16) * e^(3x) * sin(4x) - (9/16) * t
Solve for t
(25/16) * t = (1/16) * e^(3x) * (3 * sin(4x) - 4 * cos(4x))
25 * t = e^(3x) * (3 * sin(4x) - 4 * cos(4x))
t = (1/25) * e^(3x) * (3 * sin(4x) - 4 * cos(4x))
Add in the constant of integration
t = (1/25) * e^(3x) * (3 * sin(4x) - 4 * cos(4x)) + C
There you go,
int(u * dv) = u * v - int(v * du)
u = e^(3x)
du = 3 * e^(3x) * dx
dv = sin(4x) * dx
v = (-1/4) * cos(4x)
int(e^(3x) * sin(4x) * dx) = (-1/4) * e^(3x) * cos(4x) - int((-1/4) * 3 * e^(3x) * cos(4x) * dx)
int(e^(3x) * sin(4x) * dx) = (-1/4) * e^(3x) * cos(4x) + (3/4) * int(e^(3x) * cos(4x) * dx)
u = e^(3x)
du = 3 * e^(3x) * dx
dv = cos(4x) * dx
v = (1/4) * sin(4x)
int(e^(3x) * sin(4x) * dx) = (-1/4) * e^(3x) * cos(4x) + (3/4) * ((1/4) * e^(3x) * sin(4x) - int((3/4) * e^(3x) * sin(4x) * dx))
Let int(e^(3x) * sin(4x) * dx) = t
t = (-1/4) * e^(3x) * cos(4x) + (3/16) * e^(3x) * sin(4x) - (9/16) * t
Solve for t
(25/16) * t = (1/16) * e^(3x) * (3 * sin(4x) - 4 * cos(4x))
25 * t = e^(3x) * (3 * sin(4x) - 4 * cos(4x))
t = (1/25) * e^(3x) * (3 * sin(4x) - 4 * cos(4x))
Add in the constant of integration
t = (1/25) * e^(3x) * (3 * sin(4x) - 4 * cos(4x)) + C
There you go,
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