解三角方程cosx-sinx=1

sinx-cosx=-1
√2sin(x-π/4)=-1
sin(x-π/4)=-√2/2
x-π/4=2kπ-π/4或x-π/4=2kπ-3π/4
所以x=2kπ或x=2kπ-π/2,k是整数

x等于0度就行了

cosx=1+sinx
cosx^2+sinx^2=1
2sinx^2+2sinx+1=1
sinx(sinx+1)=0
sinx=0或sinx=-1

√2sin(45-x)=1
sin(45-x)=√2/2
45-x=45+2k∏
45-x=135+2k∏
x=-2k∏ Or ∏/2-2k∏