∵x为第二象限的角,且cosx/2+sinx/2=-根号5/2
∴kπ+π/4<x/2<kπ+π/2,且k为奇数.
(cosx/2+sinx/2)^2=(-根号5/2)^2
1+sinx=5/4
sinx=1/4
(sinx/2-cosx/2)^2=1-sinx=1-1/4=3/4
∵sinx/2-cosx/2<0
∴sinx/2-cosx/2=-根号3/2
∵x为第二象限的角,且cosx/2+sinx/2=-根号5/2
∴kπ+π/4<x/2<kπ+π/2,且k为奇数.
(cosx/2+sinx/2)^2=(-根号5/2)^2
1+sinx=5/4
sinx=1/4
(sinx/2-cosx/2)^2=1-sinx=1-1/4=3/4
∵sinx/2-cosx/2<0
∴sinx/2-cosx/2=-根号3/2