(1-sin^4a-cos^4)/(sin^2a-sin^4a) 化简

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(1-sin^4a-cos^4)/(sin^2a-sin^4a) 化简

(1-sin^4a-cos^4)/(sin^2a-sin^4a) 化简
(1-sin^4a-cos^4)/(sin^2a-sin^4a) 化简

(1-sin^4a-cos^4)/(sin^2a-sin^4a) 化简
(1-sin^4a-cos^4)/(sin^2a-sin^4a)
={1-[(sina)^2+(cosa)^2]^2+2(sina)^2*(cosa)^2}/{(sina)^2*[1-(sina)^2]}
=[2(sina)^2*(cosa)^2]/[(sina)^2*(cosa)^2]
=2

化简1-sin^4a-cos^4a/1-sin^6a-cos^6a 1-sin^6a-cos^6a分之1-sin^4a-cos^4a 化简 (1-sin^6a-cos^6a)/(1-sin^4a-cos^4a)=? (1-sin^4a-cos^4a)/(1-sin^6a-cos^6a) sin(α+π/3)+sinα=负5分之4根号3 α∈(-π/2,0)求cosα怎样从9/4*sin²α=9/4(1-cos²α)=3/4*cos²a+12/5*cosx+48/25化为cos²α+4/5*cosα-11/100=0呀sin(α+π/3)+sinα=-4√3/5sinαcosπ/3+cosαsinπ/3+sinα=-4√3/53/2*si 化简:(sin^6a+cos^6a-1) / (sin^4ª+cos^4a-1) 由cos(a+b)=cos a cos b-sin a sin b cos(a-b)=cos a cos b+sin a sin b解题设a为锐角,证:1、2分之根3乘cos a + 2分之1乘sin a=cos(6分之π-a)2、cos a-sin a=根号2cos(4分之π+a) 化简 1-sin^4a-cos^4a/cos^2a-cos^4a 化简(1-sin^6 a-cos^6 a)/(cos^2 a-cos^4 a)== 8sin(45+a)sin(45-a)=1,sin^4a-cos^4a= (1-sin^6a-cos^6a)/(sin^2a-sin^4a) cosA+cos^2A=1,sin^2A+sin^4A+sin^8A sin^4+sin^2cos^2+cos^2a= 求证1/sin^2a+3/cos^2a>=4+2根号下31/sin²a +3/cos²a=(sin²a+cos²a)/sin²a +3(sin²a+cos²a)/cos²a=1+cos²a/sin²a+3+3sin²a/cos²a=4+cos²a/sin²a+3sin²a/cos²a≥4+2√[(cos (1-sin^4a-cos^4)/(sin^2a-sin^4a) 化简 化简1-cos^4a-sin^4a/1-cos^6-sin^6acos^6应为cos^6a =1-(sin^6a+cos^6a) ------(1)=1-(sin^a+cos^a)(sin^4 a-sin^acos6a+cos^4 a) --------(2)由(1)怎么能到(2)呢=1-(sin^6a+cos^6a)=1-(sin^2a+cos^2a)(sin^4 a-sin^2acos^2a+cos^4a) 倍角化简练习册上有一题是这样的.cos(pi/7)cos(2pi/7)cos(4pi/7).然后分子分母同乘以sin(pi/7).就变成:sin(pi/7)cos(pi/7)cos(2pi/7)cos(4pi/7) / sin(pi/7);看不懂的地方在这里,不知道是做了什么运算:(1/2)si