笑傲江湖同人all东方:2sin(a+45)sin(a-45)=sin^2a-cos^2a
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sin(a-45)
=sin(a+45-90)
=-sin[90-(a+45)]
=-cos(a+45)
2sin(a+45)sin(a-45)=sin^2a-cos^2a
sin^2a-cos^2a+2sin(a+45)cos(a+45)=0
sin^2a-cos^2a+sin(2a+90)=0
sin^2a-cos^2a+cos2a=0
-cos2a+cos2a=0
0=0
2sin(a+45)sin(a-45)=sin^2a-cos^2a
化简:sin^2(A-30度)+sin^2(A+30度)-sin^2A
SIN(90度+A)=?
sin a + cos a = m . 求 sin a -cos a (0度< a <45度)
sin(-a)=什么?
OP1=(cos a ,sin a ),op2=(2 sin a ,2-cos a )
化简 1+sin(a-2派)sin(a+派)-2cos平方(-a)
已知:sinA+sin^2A=1 求sin^2+sin^4的值
2sin(a+派/4)cos(b+派/4)=cos(a+b)+sin(a-b)
2sin(a+派/4)cos(b+派/4)=cos(a+b)+sin(a-b).