求满足方程(tanx)^4+(tany)^4+2(cotx)^2(coty)^2=3+sin^2 (x+y)的所有实数对(x,y)_数学解答

求满足方程(tanx)^4+(tany)^4+2(cotx)^2(coty)^2=3+sin^2 (x+y)的所有实数对(x,y)

人气：159 ℃　时间：2020-02-03 04:52:19

解答

(tanx)^4+(tany)^4>=2(tanx)^2(tany)^2
2(tanx)^2(tany)^2+2/[(tanx)^2(tany)^2]>=4
3+[sin(x+y)]^2