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人気のある三角関数 >

tan(2x)=cos(2x),0<= x<= pi

解

tan (2 x) = cos (2 x), 0 \leq x \leq π

解

x = \frac{0.66623 \dots}{2}, x = \frac{π - 0.66623 \dots}{2}

+1

度

x = 19.08635 \dots^{\circ}, x = 70.91364 \dots^{\circ}

解答ステップ

tan (2 x) = cos (2 x), 0 \leq x \leq π

両辺から

cos (2 x)

を引く

tan (2 x) - cos (2 x) = 0

サイン, コサインで表わす

\frac{sin ( 2 x )}{cos ( 2 x )} - cos (2 x) = 0

簡素化

\frac{sin ( 2 x )}{cos ( 2 x )} - cos (2 x) : \frac{sin ( 2 x ) - cos ^{2} ( 2 x )}{cos ( 2 x )}

\frac{sin ( 2 x )}{cos ( 2 x )} - cos (2 x)

元を分数に変換する:

cos (2 x) = \frac{cos ( 2 x ) cos ( 2 x )}{cos ( 2 x )}

= \frac{sin ( 2 x )}{cos ( 2 x )} - \frac{cos ( 2 x ) cos ( 2 x )}{cos ( 2 x )}

分母が等しいので, 分数を組み合わせる:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{sin ( 2 x ) - cos ( 2 x ) cos ( 2 x )}{cos ( 2 x )}

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

sin (2 x) - cos (2 x) cos (2 x)

cos (2 x) cos (2 x) = cos^{2} (2 x)

cos (2 x) cos (2 x)

指数の規則を適用する:

a^{b} \cdot a^{c} = a^{b + c}

cos (2 x) cos (2 x) = cos^{1 + 1} (2 x)

= cos^{1 + 1} (2 x)

数を足す:

1 + 1 = 2

= cos^{2} (2 x)

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

= \frac{sin ( 2 x ) - cos ^{2} ( 2 x )}{cos ( 2 x )}

\frac{sin ( 2 x ) - cos ^{2} ( 2 x )}{cos ( 2 x )} = 0

\frac{f ( x )}{g ( x )} = 0 \Rightarrow f (x) = 0

sin (2 x) - cos^{2} (2 x) = 0

両辺に

cos^{2} (2 x)

を足す

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

両辺を2乗する

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

両辺から

(cos^{2} (2 x))^{2}

を引く

sin^{2} (2 x) - cos^{4} (2 x) = 0

因数

sin^{2} (2 x) - cos^{4} (2 x) : (sin (2 x) + cos^{2} (2 x)) (sin (2 x) - cos^{2} (2 x))

sin^{2} (2 x) - cos^{4} (2 x)

指数の規則を適用する:

a^{b c} = (a^{b})^{c}

cos^{4} (2 x) = (cos^{2} (2 x))^{2}

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

2乗の差の公式を適用する:

x^{2} - y^{2} = (x + y) (x - y)

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

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

(sin (2 x) + cos^{2} (2 x)) (sin (2 x) - cos^{2} (2 x)) = 0

各部分を別個に解く

sin (2 x) + cos^{2} (2 x) = 0 or sin (2 x) - cos^{2} (2 x) = 0

sin (2 x) + cos^{2} (2 x) = 0, 0 \leq x \leq π : x = \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

sin (2 x) + cos^{2} (2 x) = 0, 0 \leq x \leq π

三角関数の公式を使用して書き換える

cos^{2} (2 x) + sin (2 x)

ピタゴラスの公式を使用する:

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

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

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

1 + sin (2 x) - sin^{2} (2 x) = 0

置換で解く

1 + sin (2 x) - sin^{2} (2 x) = 0

仮定:

sin (2 x) = u

1 + u - u^{2} = 0

1 + u - u^{2} = 0 : u = - \frac{- 1 + 5}{2}, u = \frac{1 + 5}{2}

1 + u - u^{2} = 0

標準的な形式で書く

a x^{2} + b x + c = 0

- u^{2} + u + 1 = 0

解くとthe二次式

- u^{2} + u + 1 = 0

二次Equationの公式:

次の場合:

a = - 1, b = 1, c = 1

u_{1, 2} = \frac{- 1 \pm 1 ^{2} - 4 ( - 1 ) \cdot 1}{2 ( - 1 )}

u_{1, 2} = \frac{- 1 \pm 1 ^{2} - 4 ( - 1 ) \cdot 1}{2 ( - 1 )}

1^{2} - 4 (- 1) \cdot 1 = 5

1^{2} - 4 (- 1) \cdot 1

規則を適用

1^{a} = 1

1^{2} = 1

= 1 - 4 (- 1) \cdot 1

規則を適用

- (- a) = a

= 1 + 4 \cdot 1 \cdot 1

数を乗じる:

4 \cdot 1 \cdot 1 = 4

= 1 + 4

数を足す:

1 + 4 = 5

= 5

u_{1, 2} = \frac{- 1 \pm 5}{2 ( - 1 )}

解を分離する

u_{1} = \frac{- 1 + 5}{2 ( - 1 )}, u_{2} = \frac{- 1 - 5}{2 ( - 1 )}

u = \frac{- 1 + 5}{2 ( - 1 )} : - \frac{- 1 + 5}{2}

\frac{- 1 + 5}{2 ( - 1 )}

括弧を削除する:

(- a) = - a

= \frac{- 1 + 5}{- 2 \cdot 1}

数を乗じる:

2 \cdot 1 = 2

= \frac{- 1 + 5}{- 2}

分数の規則を適用する:

\frac{a}{- b} = - \frac{a}{b}

= - \frac{- 1 + 5}{2}

u = \frac{- 1 - 5}{2 ( - 1 )} : \frac{1 + 5}{2}

\frac{- 1 - 5}{2 ( - 1 )}

括弧を削除する:

(- a) = - a

= \frac{- 1 - 5}{- 2 \cdot 1}

数を乗じる:

2 \cdot 1 = 2

= \frac{- 1 - 5}{- 2}

分数の規則を適用する:

\frac{- a}{- b} = \frac{a}{b}

- 1 - 5 = - (1 + 5)

= \frac{1 + 5}{2}

二次equationの解:

u = - \frac{- 1 + 5}{2}, u = \frac{1 + 5}{2}

代用を戻す

u = sin (2 x)

sin (2 x) = - \frac{- 1 + 5}{2}, sin (2 x) = \frac{1 + 5}{2}

sin (2 x) = - \frac{- 1 + 5}{2}, sin (2 x) = \frac{1 + 5}{2}

sin (2 x) = - \frac{- 1 + 5}{2}, 0 \leq x \leq π : x = \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

sin (2 x) = - \frac{- 1 + 5}{2}, 0 \leq x \leq π

三角関数の逆数プロパティを適用する

sin (2 x) = - \frac{- 1 + 5}{2}

以下の一般解

sin (2 x) = - \frac{- 1 + 5}{2}

sin (x) = - a \Rightarrow x = arcsin (- a) + 2 πn, x = π + arcsin (a) + 2 πn

2 x = arcsin (- \frac{- 1 + 5}{2}) + 2 πn, 2 x = π + arcsin (\frac{- 1 + 5}{2}) + 2 πn

2 x = arcsin (- \frac{- 1 + 5}{2}) + 2 πn, 2 x = π + arcsin (\frac{- 1 + 5}{2}) + 2 πn

解く

2 x = arcsin (- \frac{- 1 + 5}{2}) + 2 πn : x = - \frac{arcsin ( \frac{5 - 1}{2} )}{2} + πn

2 x = arcsin (- \frac{- 1 + 5}{2}) + 2 πn

簡素化

arcsin (- \frac{- 1 + 5}{2}) + 2 πn : - arcsin (\frac{5 - 1}{2}) + 2 πn

arcsin (- \frac{- 1 + 5}{2}) + 2 πn

次のプロパティを使用する:

arcsin (- x) = - arcsin (x)

arcsin (- \frac{5 - 1}{2}) = - arcsin (\frac{5 - 1}{2})

= - arcsin (\frac{5 - 1}{2}) + 2 πn

2 x = - arcsin (\frac{5 - 1}{2}) + 2 πn

以下で両辺を割る

2

2 x = - arcsin (\frac{5 - 1}{2}) + 2 πn

以下で両辺を割る

2

\frac{2 x}{2} = - \frac{arcsin ( \frac{5 - 1}{2} )}{2} + \frac{2 πn}{2}

簡素化

x = - \frac{arcsin ( \frac{5 - 1}{2} )}{2} + πn

x = - \frac{arcsin ( \frac{5 - 1}{2} )}{2} + πn

解く

2 x = π + arcsin (\frac{- 1 + 5}{2}) + 2 πn : x = \frac{π}{2} + \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

2 x = π + arcsin (\frac{- 1 + 5}{2}) + 2 πn

以下で両辺を割る

2

2 x = π + arcsin (\frac{- 1 + 5}{2}) + 2 πn

以下で両辺を割る

2

\frac{2 x}{2} = \frac{π}{2} + \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + \frac{2 πn}{2}

簡素化

x = \frac{π}{2} + \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

x = \frac{π}{2} + \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

x = - \frac{arcsin ( \frac{5 - 1}{2} )}{2} + πn, x = \frac{π}{2} + \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

範囲の解答

0 \leq x \leq π

x = \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

sin (2 x) = \frac{1 + 5}{2}, 0 \leq x \leq π :

解なし

sin (2 x) = \frac{1 + 5}{2}, 0 \leq x \leq π

- 1 \leq sin (x) \leq 1

解なし

すべての解を組み合わせる

x = \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

sin (2 x) - cos^{2} (2 x) = 0, 0 \leq x \leq π : x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

sin (2 x) - cos^{2} (2 x) = 0, 0 \leq x \leq π

三角関数の公式を使用して書き換える

- cos^{2} (2 x) + sin (2 x)

ピタゴラスの公式を使用する:

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

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

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

- (1 - sin^{2} (2 x)) : - 1 + sin^{2} (2 x)

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

括弧を分配する

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

マイナス・プラスの規則を適用する

- (- a) = a, - (a) = - a

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

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

- 1 + sin (2 x) + sin^{2} (2 x) = 0

置換で解く

- 1 + sin (2 x) + sin^{2} (2 x) = 0

仮定:

sin (2 x) = u

- 1 + u + u^{2} = 0

- 1 + u + u^{2} = 0 : u = \frac{- 1 + 5}{2}, u = \frac{- 1 - 5}{2}

- 1 + u + u^{2} = 0

標準的な形式で書く

a x^{2} + b x + c = 0

u^{2} + u - 1 = 0

解くとthe二次式

u^{2} + u - 1 = 0

二次Equationの公式:

次の場合:

a = 1, b = 1, c = - 1

u_{1, 2} = \frac{- 1 \pm 1 ^{2} - 4 \cdot 1 \cdot ( - 1 )}{2 \cdot 1}

u_{1, 2} = \frac{- 1 \pm 1 ^{2} - 4 \cdot 1 \cdot ( - 1 )}{2 \cdot 1}

1^{2} - 4 \cdot 1 \cdot (- 1) = 5

1^{2} - 4 \cdot 1 \cdot (- 1)

規則を適用

1^{a} = 1

1^{2} = 1

= 1 - 4 \cdot 1 \cdot (- 1)

規則を適用

- (- a) = a

= 1 + 4 \cdot 1 \cdot 1

数を乗じる:

4 \cdot 1 \cdot 1 = 4

= 1 + 4

数を足す:

1 + 4 = 5

= 5

u_{1, 2} = \frac{- 1 \pm 5}{2 \cdot 1}

解を分離する

u_{1} = \frac{- 1 + 5}{2 \cdot 1}, u_{2} = \frac{- 1 - 5}{2 \cdot 1}

u = \frac{- 1 + 5}{2 \cdot 1} : \frac{- 1 + 5}{2}

\frac{- 1 + 5}{2 \cdot 1}

数を乗じる:

2 \cdot 1 = 2

= \frac{- 1 + 5}{2}

u = \frac{- 1 - 5}{2 \cdot 1} : \frac{- 1 - 5}{2}

\frac{- 1 - 5}{2 \cdot 1}

数を乗じる:

2 \cdot 1 = 2

= \frac{- 1 - 5}{2}

二次equationの解:

u = \frac{- 1 + 5}{2}, u = \frac{- 1 - 5}{2}

代用を戻す

u = sin (2 x)

sin (2 x) = \frac{- 1 + 5}{2}, sin (2 x) = \frac{- 1 - 5}{2}

sin (2 x) = \frac{- 1 + 5}{2}, sin (2 x) = \frac{- 1 - 5}{2}

sin (2 x) = \frac{- 1 + 5}{2}, 0 \leq x \leq π : x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

sin (2 x) = \frac{- 1 + 5}{2}, 0 \leq x \leq π

三角関数の逆数プロパティを適用する

sin (2 x) = \frac{- 1 + 5}{2}

以下の一般解

sin (2 x) = \frac{- 1 + 5}{2}

sin (x) = a \Rightarrow x = arcsin (a) + 2 πn, x = π - arcsin (a) + 2 πn

2 x = arcsin (\frac{- 1 + 5}{2}) + 2 πn, 2 x = π - arcsin (\frac{- 1 + 5}{2}) + 2 πn

2 x = arcsin (\frac{- 1 + 5}{2}) + 2 πn, 2 x = π - arcsin (\frac{- 1 + 5}{2}) + 2 πn

解く

2 x = arcsin (\frac{- 1 + 5}{2}) + 2 πn : x = \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

2 x = arcsin (\frac{- 1 + 5}{2}) + 2 πn

以下で両辺を割る

2

2 x = arcsin (\frac{- 1 + 5}{2}) + 2 πn

以下で両辺を割る

2

\frac{2 x}{2} = \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + \frac{2 πn}{2}

簡素化

x = \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

x = \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

解く

2 x = π - arcsin (\frac{- 1 + 5}{2}) + 2 πn : x = \frac{π}{2} - \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

2 x = π - arcsin (\frac{- 1 + 5}{2}) + 2 πn

以下で両辺を割る

2

2 x = π - arcsin (\frac{- 1 + 5}{2}) + 2 πn

以下で両辺を割る

2

\frac{2 x}{2} = \frac{π}{2} - \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + \frac{2 πn}{2}

簡素化

x = \frac{π}{2} - \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

x = \frac{π}{2} - \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

x = \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn, x = \frac{π}{2} - \frac{arcsin ( \frac{- 1 + 5}{2} )}{2} + πn

範囲の解答

0 \leq x \leq π

x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

sin (2 x) = \frac{- 1 - 5}{2}, 0 \leq x \leq π :

解なし

sin (2 x) = \frac{- 1 - 5}{2}, 0 \leq x \leq π

- 1 \leq sin (x) \leq 1

解なし

すべての解を組み合わせる

x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

すべての解を組み合わせる

x = \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}, x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

元のequationに当てはめて解を検算する

tan (2 x) = cos (2 x)

に当てはめて解を確認する

equationに一致しないものを削除する。

解答を確認する

\frac{π + arcsin ( \frac{5 - 1}{2} )}{2} :

偽

\frac{π + arcsin ( \frac{5 - 1}{2} )}{2}

挿入

n = 1

\frac{π + arcsin ( \frac{5 - 1}{2} )}{2}

tan (2 x) = cos (2 x)

の挿入向け

x = \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}

tan 2 \cdot \frac{π + arcsin ( \frac{5 - 1}{2} )}{2} = cos 2 \cdot \frac{π + arcsin ( \frac{5 - 1}{2} )}{2}

改良

0.78615 \dots = - 0.78615 \dots

\Rightarrow 偽

解答を確認する

\frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2} :

偽

\frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

挿入

n = 1

\frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

tan (2 x) = cos (2 x)

の挿入向け

x = \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

tan 2 \cdot \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2} = cos 2 \cdot \frac{- arcsin ( \frac{5 - 1}{2} ) + 2 π}{2}

改良

- 0.78615 \dots = 0.78615 \dots

\Rightarrow 偽

解答を確認する

\frac{arcsin ( \frac{5 - 1}{2} )}{2} :

真

\frac{arcsin ( \frac{5 - 1}{2} )}{2}

挿入

n = 1

\frac{arcsin ( \frac{5 - 1}{2} )}{2}

tan (2 x) = cos (2 x)

の挿入向け

x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}

tan 2 \cdot \frac{arcsin ( \frac{5 - 1}{2} )}{2} = cos 2 \cdot \frac{arcsin ( \frac{5 - 1}{2} )}{2}

改良

0.78615 \dots = 0.78615 \dots

\Rightarrow 真

解答を確認する

\frac{π - arcsin ( \frac{5 - 1}{2} )}{2} :

真

\frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

挿入

n = 1

\frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

tan (2 x) = cos (2 x)

の挿入向け

x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

tan 2 \cdot \frac{π - arcsin ( \frac{5 - 1}{2} )}{2} = cos 2 \cdot \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

改良

- 0.78615 \dots = - 0.78615 \dots

\Rightarrow 真

x = \frac{arcsin ( \frac{5 - 1}{2} )}{2}, x = \frac{π - arcsin ( \frac{5 - 1}{2} )}{2}

10進法形式で解を証明する

x = \frac{0.66623 \dots}{2}, x = \frac{π - 0.66623 \dots}{2}

グラフ

人気の例

5sin(2x)=5cos(x),0<= x<= 2pi

5 sin (2 x) = 5 cos (x), 0 \leq x \leq 2 π

solvefor x,f=cos(x)cos(hy)

so l v e f or x, f = cos (x) cos (h y)

tan (x) = - \frac{1}{10}

tan(4x)*cot(x+60)=1

tan (4 x) \cdot cot (x + 60) = 1

sin^2(A)+cos^2(A)+sin(A)-2=0

sin^{2} (A) + cos^{2} (A) + sin (A) - 2 = 0