已知sin(a+π/4)+sin(a-π/4)=√2/3则sin(a-π/4)/1-cos2a-sin2a的值

已知sin(a+π/4)+sin(a-π/4)=√2/3则sin(a-π/4)/1-cos2a-sin2a的值
已知sin(a+π/4)+sin(a-π/4)=√2/3则sin(a-π/4)/1-cos2a-sin2a的值

已知sin(a+π/4)+sin(a-π/4)=√2/3则sin(a-π/4)/1-cos2a-sin2a的值
由sin(a+π/4)+sin(a-π/4)=√2/3可得
(√2/2)sina+(√2/2)cosa+(√2/2)sina-(√2/2)cosa=√2/3
可知sina=1/3
然后将题目中的三角函数都化成sina形式,
（顺便一说,你题目中的1-cos2a-sin2a是要加括号的吗?因为不敢确定,所以没解,还望见谅）