2+cos(x)=0

解答

2 + cos (x) = 0

x \in R 无解

求解步骤

2 + cos (x) = 0

将

2

到右边

2 + cos (x) = 0

两边减去

2

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

化简

cos (x) = - 2

cos (x) = - 2

- 1 \leq cos (x) \leq 1

x \in R 无解

cos (θ) + 2 cos^{2} (θ) = 0

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

sin (x) = 2 sin (x) + 1

4 cosh (x) - sinh (x) = 8

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