sin(pai-a)-cos(pai+a)=√2/3,
即sin(a)+cos(a)=√2/3
两边平方得:
1+2*sin(a)cos(a) = 2/9
所以,
2*sin(a)cos(a) = -7/9
将sin(a)-cos(a)两边平方得,
1-2*sin(a)cos(a) = 16/9;
pai/2
sin(pai-a)-cos(pai+a)=√2/3,
即sin(a)+cos(a)=√2/3
两边平方得:
1+2*sin(a)cos(a) = 2/9
所以,
2*sin(a)cos(a) = -7/9
将sin(a)-cos(a)两边平方得,
1-2*sin(a)cos(a) = 16/9;
pai/2