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受欢迎的三角函数 >

-cos(x)=cos(x)

解答

- cos (x) = cos (x)

解答

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

+1

度数

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

求解步骤

- cos (x) = cos (x)

用替代法求解

- cos (x) = cos (x)

令

: cos (x) = u

- u = u

- u = u : u = 0

- u = u

将

u

para o lado esquerdo

- u = u

两边减去

u

- u - u = u - u

化简

- 2 u = 0

- 2 u = 0

两边除以

- 2

- 2 u = 0

两边除以

- 2

\frac{- 2 u}{- 2} = \frac{0}{- 2}

化简

u = 0

u = 0

u = cos (x)

代回

cos (x) = 0

cos (x) = 0

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

cos (x) = 0

cos (x) = 0

的通解

cos (x)

周期表（周期为

2 πn

）：

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 = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

合并所有解

x = \frac{π}{2} + 2 πn, x = \frac{3 π}{2} + 2 πn

作图

流行的例子

sqrt(2)cos(θ)-1=0

2 cos (θ) - 1 = 0

6sin^2(x)-7sin(x)+2=0

6 sin^{2} (x) - 7 sin (x) + 2 = 0

5sin(2x)=2tan(30)

5 sin (2 x) = 2 tan (3 0^{\circ})

6sin^2(x)+cos(x)-4=0

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

sin(2x)sin(x)+cos(x)=0

sin (2 x) sin (x) + cos (x) = 0