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人気のある三角関数 >

cos^4(x)-1=0

解

cos^{4} (x) - 1 = 0

解

x = 2 πn, x = π + 2 πn

+1

度

x = 0^{\circ} + 36 0^{\circ} n, x = 18 0^{\circ} + 36 0^{\circ} n

解答ステップ

cos^{4} (x) - 1 = 0

置換で解く

cos^{4} (x) - 1 = 0

仮定:

cos (x) = u

u^{4} - 1 = 0

u^{4} - 1 = 0 : u = 1, u = - 1, u = i, u = - i

u^{4} - 1 = 0

1

を右側に移動します

u^{4} - 1 = 0

両辺に

1

を足す

u^{4} - 1 + 1 = 0 + 1

簡素化

u^{4} = 1

u^{4} = 1

equationを

v = u^{2}

と以下で書き換える:

v^{2} = u^{4}

v^{2} = 1

解く

v^{2} = 1 : v = 1, v = - 1

v^{2} = 1

(g (x))^{2} = f (a)

の場合, 解は

g (x) = f (a), - f (a)

v = 1, v = - 1

v = 1, v = - 1

再び

v = u^{2}

に置き換えて以下を解く:

u

解く

u^{2} = 1 : u = 1, u = - 1

u^{2} = 1

規則を適用

1 = 1

u^{2} = 1

x^{2} = f (a)

の場合, 解は

x = f (a), - f (a)

u = 1, u = - 1

1 = 1

1

規則を適用

1 = 1

= 1

- 1 = - 1

- 1

規則を適用

1 = 1

= - 1

u = 1, u = - 1

解く

u^{2} = - 1 : u = i, u = - i

u^{2} = - 1

規則を適用

1 = 1

u^{2} = - 1

x^{2} = f (a)

の場合, 解は

x = f (a), - f (a)

u = - 1, u = - - 1

簡素化

- 1 : i

- 1

虚数の規則を適用する:

- 1 = i

= i

簡素化

- - 1 : - i

- - 1

虚数の規則を適用する:

- 1 = i

= - i

u = i, u = - i

解答は

u = 1, u = - 1, u = i, u = - i

代用を戻す

u = cos (x)

cos (x) = 1, cos (x) = - 1, cos (x) = i, cos (x) = - i

cos (x) = 1, cos (x) = - 1, cos (x) = i, cos (x) = - i

cos (x) = 1 : x = 2 πn

cos (x) = 1

以下の一般解

cos (x) = 1

cos (x)

2 πn

循環を含む周期性テーブル:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

x = 0 + 2 πn

x = 0 + 2 πn

解く

x = 0 + 2 πn : x = 2 πn

x = 0 + 2 πn

0 + 2 πn = 2 πn

x = 2 πn

x = 2 πn

cos (x) = - 1 : x = π + 2 πn

cos (x) = - 1

以下の一般解

cos (x) = - 1

cos (x)

2 πn

循環を含む周期性テーブル:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

x = π + 2 πn

x = π + 2 πn

cos (x) = i :

解なし

cos (x) = i

解なし

cos (x) = - i :

解なし

cos (x) = - i

解なし

すべての解を組み合わせる

x = 2 πn, x = π + 2 πn

グラフ

人気の例

2sin(x)=sqrt(3),0<= x<2pi

2 sin (x) = 3, 0 \leq x < 2 π

sec^2(x)+0.5tan(x)=1

sec^{2} (x) + 0.5 tan (x) = 1

8sin(x)=cos(x)-3

8 sin (x) = cos (x) - 3

cos(2x)-sin^2(x)=1

cos (2 x) - sin^{2} (x) = 1

tan (a) = 2