/ 2 \ | tan (2*x) | lim |---------------------| x->0+\3*x*cos(9*x)*sin(3*x)/
Limit(tan(2*x)^2/((((3*x)*cos(9*x))*sin(3*x))), x, 0)
/ 2 \ | tan (2*x) | lim |---------------------| x->0+\3*x*cos(9*x)*sin(3*x)/
4/9
= 0.444444444444444
/ 2 \ | tan (2*x) | lim |---------------------| x->0-\3*x*cos(9*x)*sin(3*x)/
4/9
= 0.444444444444444
= 0.444444444444444