信阳市肿瘤医院招聘:化简：sin^2(A-30)+sin^2(A+30)-sin^2A

来源：百度文库编辑：神马品牌网时间：2024/05/03 03:00:44

sin^2(A-30)+sin^2(A+30)-sin^2A
=[1-cos(2A-60)]/2+[1-cos(2A+60)]/2+(cos2A-1)/2
=1/2-(cos2Acos60+sin2Asin60)-(cos2Acos60-sin2Asin60)+cos2A
=1/2-2cos2Acos60+cos2A
=1/2

sin^2(A-30)+sin^2(A+30)-sin^2A
=(sin(A-30)+sin(A+30))^2-2sin(A-30)sin(A+30)-4sin^2Acos^2A
=(1/2)sin^2A+(3/2)cos^2A-4sin^2Acos^2A
=4sin^4A-5sin^2A+(3/2)

我有八年没有做过了，可能做错了，呵呵，别见怪哈。

化简：sin^2(A-30)+sin^2(A+30)-sin^2A 化简：sin^2(A-30度）＋sin^2（A＋30度）-sin^2A 2sin（a+45）sin（a-45）=sin^2a-cos^2a 已知：sinA+sin^2A=1 求sin^2+sin^4的值化简 1+sin(a－2派）sin(a+派）－2cos平方（－a) OP1=(cos a ,sin a ),op2=(2 sin a ,2-cos a ) 化简(2sin^2a+sin2a)/(1+tana) 3sin b=sin(a+b)求证tan(a+b)=2tan a sin(a+B)cosa-1/2{sin[(a+B)+a]-sinB}= 以知cos(a+β )=-1,求证sin(2a+β )+sinβ=0