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受欢迎的三角函数 >

cos(x)=(-1)/4

解答

cos (x) = \frac{- 1}{4}

解答

x = 1.82347 \dots + 2 πn, x = - 1.82347 \dots + 2 πn

+1

度数

x = 104.47751 \dots^{\circ} + 36 0^{\circ} n, x = - 104.47751 \dots^{\circ} + 36 0^{\circ} n

求解步骤

cos (x) = \frac{- 1}{4}

使用分式法则:

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

cos (x) = - \frac{1}{4}

使用反三角函数性质

cos (x) = - \frac{1}{4}

cos (x) = - \frac{1}{4}

的通解

cos (x) = - a \Rightarrow x = arccos (- a) + 2 πn, x = - arccos (- a) + 2 πn

x = arccos (- \frac{1}{4}) + 2 πn, x = - arccos (- \frac{1}{4}) + 2 πn

x = arccos (- \frac{1}{4}) + 2 πn, x = - arccos (- \frac{1}{4}) + 2 πn

以小数形式表示解

x = 1.82347 \dots + 2 πn, x = - 1.82347 \dots + 2 πn

作图

流行的例子

tan(θ)=sqrt(7/2)

tan (θ) = \frac{7}{2}

2 \cdot sin (2 x + 1 5^{\circ}) = 1

cos(2x)+3cos(x)+2=0, pi/2 <= x<= pi

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

sin^{2} (4 x) = 1

sin(2x+60)= 1/2

sin (2 x + 60) = \frac{1}{2}