Question

已知tan(a)=3,求sin^2(a)+2sin(a)cos(a)+3cos^2(a)/sin(a)cos(a)+co

Answer 1

sin^2(a)+2sin(a)cos(a)+3cos^2(a)/sin(a)cos(a)+cos^2(a)

分子分母同除以cos²a,得

原式=(tan²a+2tana+3)/(tana+1)

=(9+6+3)/(3+1)

=18/4

=9/2