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受欢迎的三角函数 >

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

解答

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

解答

x = 2 πn

+1

度数

x = 0^{\circ} + 36 0^{\circ} n

求解步骤

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

使用三角恒等式改写

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

使用毕达哥拉斯恒等式:

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

= 1

1 = cos (x)

交换两边

cos (x) = 1

cos (x) = 1

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 = 0 + 2 πn

x = 0 + 2 πn

解

x = 0 + 2 πn : x = 2 πn

x = 0 + 2 πn

0 + 2 πn = 2 πn

x = 2 πn

x = 2 πn

作图

流行的例子

sin (\frac{x}{3}) = - 0.85

2 cos (3 θ) = 2

tan(θ)=2,0<θ<(pi/2),sin(θ/2)

tan (θ) = 2, 0 < θ < (\frac{π}{2}), sin (\frac{θ}{2})

sinh (a) = \frac{1}{2}

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

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