sinx*cosx=1/3,且派/4

sinx*cosx=1/3,且派/4

(sinx+cosx)^2=1+2sinxcosx=1+2/3=5/3
sinx+cosx=根号15/3
π/4sinx>cosx
sinx-cosx>0
(sinx-cosx)^2=1-2sinxcosx=1/3
sinx-cosx=√3/3
sinx=(根号15+根号3)/6