Question

数学小问2

tan15+1/tan15=?

Answer 1

tan@/2=sin@/(1+cos@)
所以答案是4

Answer 2

tan15+1/tan15=sin15/cos15+cos15/sin15=[(sin15)^2+(cos15)^2]/sin15cos15=1/sin15cos15
=2/2sin15cos15=2/sin30=4

Answer 3

tan15+1/tan15=sin15/cos15+ cos15/ sin15.把这通分答案就出来了。最后算下来等于4

Answer 4

cos15=√¯[(1+cos30)/2]
sin15=√¯[(1-cos30)/2]
tan15=sin15/cos15
=√¯(1-cos30)/(1+cos30°)
=√¯[(2-√¯3)/(2+√¯3)]
=2-√¯3
tan15+1/tan15=2-√¯3+1/(2-√¯3)=2-√¯3+(2+√¯3)=4

Answer 5

tan15+1/tan15
=sin15/cos15+cos15/sin15
=[(sin15)^2+(cos15)^2]/sin15cos15
=1/sin15cos15
=2/2sin15cos15
=2/sin30
=4

Answer 6

tan15=sin15/cos15
1/tan15=cos15/sin15
tan15+1/tan15=sin15/cos15+cos15/sin15=(sin15*sin15+cos15*cos15)/sin15*cos15
=1/[(sin30)/2]=4