化简sin的4次方α sin的2次方αcos的2次方α cos的2次方α

(sina)^6+(cosa)^6=((sina)^2)^3+((cosa)^2)^3=((sina)^2+(cosa)^2)[((sina)^2)^2-(sina)^2(cosa)^2+((cosa

sin^6A+cos^6A=(sin^2A+cos^2A)(sin^4A-sin^2A*cos^2A+cos^4A)=sin^4A-sin^2A*cos^2A+cos^4A=sin^4A+2sin^2

左边=cot²atan²a-cot²asin²a=(cotatana)²-(cosa/sina*sina)²=1-cos²a=si

(sin^2x+cos^2x)^2=1sin的4次方x＋cos的4次方x+2sin的2次方x乘cos的2次方x=1-2sin的2次方x乘cos的2次方xsin的4次方x＋cos的4次方x=1-2sin

1.（sin^4x-sin^2x）/secx=sin^2x(sin^2x-1)cosx=-sin^2xcos^2xcosx=-sin^2xcos^3x2.sin^4x-cos^4x=(sin^2x+c

因为sin²a+cos²a=1所以cos²a=1-sin²a所以左边=(sin²a+cos²a)(sin²a-cos²a

sin²a=(sina)²=(sina)×(sina)sina²=sin(a²)再问：sin（π²）怎么求呢再答：sin(π²)已经是最简了

sin^4a+cos^4a=1(sin^2a+cos^2a)^2-2sin^2acos^2a=1sinacosa=0(sina+cosa)^2=sin^2a+cos^2a+2sinacosa=1+0=

证明：因为sinα4(4次方)α+cos4(4次方）α+2sin²αcos²α=（sin²α+cos²α）²=1²所以sinα4(4次方)α

sin的4次方α-cos的4次方α=(sin的2次方α+cos的2次方α)(sin的2次方α-cos的2次方α)=sin的2次方α-cos的2次方α=2sin的2次方α-1=2*1/5-1=-3/5

3/5.再问：详细过程，谢谢。再答：cos[sin-1(4/5)]=cos[arcsin(4/5)]=±根下（1-sin^2[arcsin(4/5)]=±根下(1-(4/5)^2)=±3/5

从右边证：(1-Sinα+Cosα)^2=1+(Sinα)^2+(Cosα)^2-2Sinα+2Cosα-2SinαCosα=2-2Sinα+2Cosα-2SinαCosα=2(1-Sinα+Cosα

sin^4α+cos^2α+sin^2αcos^2α=sin^2α（sin^2α+cos^2α）+cos^2α=sin^2α+cos^2α=1,不懂可以HI我

sinα+cosα除以sinα-cosα等于2sinα+cosα=2(sinα-cosα)sinα+cosα=2sinα-2cosαsinα=3cosαsin^2α=(3cosα)^2sin^2α=9

∵左边=sin^4+cos^4=(sin^2+cos^2)^2-2sin^2cos^2而sin^2+cos^2=1,∴sin^4+cos^4=1－2sin^2cos^2=右边

sinα+3cosα=0sinα=-3cosαsinα/cosα=-3tanα=-32sin²α-3sinαcosα+2=(2sin²α-3sinαcosα+2)/1=[2sin&

sinα+cosα=√21+2sinαcosα=2sin2α=12α=2kπ+π/2α=kπ+π/4sin的4次方α-cos的4次方α=0

(一)(sinα)^4-(sinα)^2+(cosα)^2=(1-cosα^2)^2-(1-cosα^2)+(cosα)^2=1-2cosα^2+cosα^4-1+cosα^2+cosα^2=cosα

cosa+cos²a=1cosa=1-cos²acosa=sin²asina+sin²a+sin^4a+sin^6a=sina+cosa+sin^4a(1+si