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人気のある三角関数 >

2cos^2(x)-sqrt(3)cos(x)=0,0<x<180

解

2 cos^{2} (x) - 3 cos (x) = 0, 0^{\circ} < x < 18 0^{\circ}

解

x = 3 0^{\circ}, x = 9 0^{\circ}

+1

ラジアン

x = \frac{π}{6}, x = \frac{π}{2}

解答ステップ

2 cos^{2} (x) - 3 cos (x) = 0, 0^{\circ} < x < 18 0^{\circ}

置換で解く

2 cos^{2} (x) - 3 cos (x) = 0

仮定:

cos (x) = u

2 u^{2} - 3 u = 0

2 u^{2} - 3 u = 0 : u = \frac{3}{2}, u = 0

2 u^{2} - 3 u = 0

解くとthe二次式

2 u^{2} - 3 u = 0

二次Equationの公式:

次の場合:

a = 2, b = - 3, c = 0

u_{1, 2} = \frac{- ( - 3 ) \pm ( - 3 ) ^{2} - 4 \cdot 2 \cdot 0}{2 \cdot 2}

u_{1, 2} = \frac{- ( - 3 ) \pm ( - 3 ) ^{2} - 4 \cdot 2 \cdot 0}{2 \cdot 2}

(- 3)^{2} - 4 \cdot 2 \cdot 0 = 3

(- 3)^{2} - 4 \cdot 2 \cdot 0

(- 3)^{2} = 3

(- 3)^{2}

指数の規則を適用する:

n

が偶数であれば

(- a)^{n} = a^{n}

(- 3)^{2} = (3)^{2}

= (3)^{2}

累乗根の規則を適用する:

a = a^{\frac{1}{2}}

= (3^{\frac{1}{2}})^{2}

指数の規則を適用する:

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

= 3^{\frac{1}{2} \cdot 2}

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

\frac{1}{2} \cdot 2

分数を乗じる:

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

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

共通因数を約分する:

2

= 1

= 3

4 \cdot 2 \cdot 0 = 0

4 \cdot 2 \cdot 0

規則を適用

0 \cdot a = 0

= 0

= 3 - 0

数を引く:

3 - 0 = 3

= 3

u_{1, 2} = \frac{- ( - 3 ) \pm 3}{2 \cdot 2}

解を分離する

u_{1} = \frac{- ( - 3 ) + 3}{2 \cdot 2}, u_{2} = \frac{- ( - 3 ) - 3}{2 \cdot 2}

u = \frac{- ( - 3 ) + 3}{2 \cdot 2} : \frac{3}{2}

\frac{- ( - 3 ) + 3}{2 \cdot 2}

規則を適用

- (- a) = a

= \frac{3 + 3}{2 \cdot 2}

類似した元を足す:

3 + 3 = 23

= \frac{2 3}{2 \cdot 2}

数を乗じる:

2 \cdot 2 = 4

= \frac{2 3}{4}

共通因数を約分する:

2

= \frac{3}{2}

u = \frac{- ( - 3 ) - 3}{2 \cdot 2} : 0

\frac{- ( - 3 ) - 3}{2 \cdot 2}

規則を適用

- (- a) = a

= \frac{3 - 3}{2 \cdot 2}

類似した元を足す:

3 - 3 = 0

= \frac{0}{2 \cdot 2}

数を乗じる:

2 \cdot 2 = 4

= \frac{0}{4}

規則を適用

\frac{0}{a} = 0, a \neq = 0

= 0

二次equationの解:

u = \frac{3}{2}, u = 0

代用を戻す

u = cos (x)

cos (x) = \frac{3}{2}, cos (x) = 0

cos (x) = \frac{3}{2}, cos (x) = 0

cos (x) = \frac{3}{2}, 0 < x < 18 0^{\circ} : x = 3 0^{\circ}

cos (x) = \frac{3}{2}, 0 < x < 18 0^{\circ}

以下の一般解

cos (x) = \frac{3}{2}

cos (x)

36 0^{\circ} n

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 = 3 0^{\circ} + 36 0^{\circ} n, x = 33 0^{\circ} + 36 0^{\circ} n

x = 3 0^{\circ} + 36 0^{\circ} n, x = 33 0^{\circ} + 36 0^{\circ} n

範囲の解答

0 < x < 18 0^{\circ}

x = 3 0^{\circ}

cos (x) = 0, 0 < x < 18 0^{\circ} : x = 9 0^{\circ}

cos (x) = 0, 0 < x < 18 0^{\circ}

以下の一般解

cos (x) = 0

cos (x)

36 0^{\circ} n

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 = 9 0^{\circ} + 36 0^{\circ} n, x = 27 0^{\circ} + 36 0^{\circ} n

x = 9 0^{\circ} + 36 0^{\circ} n, x = 27 0^{\circ} + 36 0^{\circ} n

範囲の解答

0 < x < 18 0^{\circ}

x = 9 0^{\circ}

すべての解を組み合わせる

x = 3 0^{\circ}, x = 9 0^{\circ}

グラフ

人気の例

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\frac{tan ( x )}{cos ( x )} = \frac{2}{3}

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tan (x) + 2 cos (x) csc (x) = sec (x) cos (x) + cot (x)

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cos(a)=(sqrt(5))/5

cos (a) = \frac{5}{5}

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