(1-sin ^ 6 a-cos ^ 6 A) / (sin ^ 2 a-SiN ^ 4 a),

(1-sin ^ 6 a-cos ^ 6 A) / (sin ^ 2 a-SiN ^ 4 a),

(1-sin^6 a-cos^6 a)/(sin^2 a-sin^4 a)=[1-(cos^6 a+sin^6 a)]/(sin^2 a-sin^4 a)=[1-(cos^2a+sin^2a)(cos^4a-sin^2a*cos^2a+sin^4a)]/sin^2a(1-sin^2a)=(1-cos^4a+sin^2a*cos^2a-sin^4a)/(sin^2a*cos^2a)=[(1-cos^...

It is known that cos (π + a) = - 1 / 2,3 / 2 π

cos(π+a)=-cosa=-1/2
cosa=1/2
sin²a+cos²a=1
In the fourth quadrant, Sina

It is proved that cos α (COS α - cos β) + sin α (sin α - sin β) = 2Sin squared (α - β) △ 2

cosα(cosα－cosβ)+ sinα(sinα－sinβ)
=cos²α-cosαcosβ+sin²α-sinαsinβ
=1-(cosαcosβ+sinαsinβ)
=1-cos(α-β)
=1-[1-2sin²(α-β)/2]
=2sin²(α-β)/2
Get the certificate

It is proved that sin square a * sin square B + cos square a * cos square B-1 / 2cos2a * cos2b = 1 / 2

sin²asin²b+cos²acos²b-1/2cos2acos2b=(1-cos²a)(1-cos²b)+cos²acos²b-1/2(2cos²a-1)(2cos²b-1)=1-cos²b-cos²a+cos²acos²b+cos²acos&#...

It is proved that cos (зззззззззззззззззззззз

Left = (cos3cosb-sin3sinb) * (cos3cosb + sin3sinb)
=Squared sincos * 3 square
=Cos square B (1-sin square 3) - Sin square 3 * sin square B
=Cos square b-sin square 3 * (COS square B + sin square B)
=Right

It is known that sin (α + π) = 4 2 sin (α + π) + 3tan (3 π - α) 4cos(α-3π)．

∵sin（α+π）=-sinα=4
5＞0，
∴sinα=-4
5＜0，
∵sinαcosα＜0，
∴cosα＞0
∴cosα=
1-16
25=3
Five
tanα=-4
Three
∴2sin(α+π)+3tan(3π-α)
4cos(α-3π)=2sinα+3tanα
4cosα=-8
5+4
Twelve
5=1

It is known that cos α = - 3 / 5, and sin α cos α

Cos α = - 3 / 5, and sin α cos α

Simplification (sin θ cos θ + cos square θ) / (sin square θ + cos square θ) This is the last step Please turn it into Tan theta

After simplification, it is equal to 1 / tanx-1

How to simplify cos square (45 ° + a) - Sin square (45 ° + a)

cos^2(45°+a)-sin^2(45°+a)=cos[2(45°+a)]=cos(90°+2a)=-sin2a.=-2sinacosa

How does (COS square + sin Square) / cos square become 1 + Tan square

Divide by cos squared