Question

设tan1234度=a,那么sin(-206度)+cos(-206度)的值为

Answer 1

tan1234=tan(8*180-206)=tan(-206)=a

sin(-206)/cos(-206)=a

sin(-206)=acos(-206)

[sin(-206)]^2+[cos(-206)]^2=1

sin(-206)=acos(-206)

[cos(-206)]^2=1/(a^2+1)

cos(-206)=-cos26