zs

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

受欢迎的三角函数 >

证明 sqrt(81-9(3sin(x))^2)=1

解答

证明

81 - 9 (3 sin (x))^{2} = 1

解答

假

求解步骤

81 - 9 (3 sin (x))^{2} = 1

两侧不相等

对于

81 - 9 (3 sin (x))^{2} = 1

代入

x = 0

81 - 9 (3 sin (0))^{2} = 9

81 - 9 (3 sin (0))^{2}

使用以下普通恒等式:

sin (0) = 0

sin (0)

sin (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} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{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} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= 0

= 81 - 9 (3 \cdot 0)^{2}

化简

81 - 9 (3 \cdot 0)^{2} : 9

81 - 9 (3 \cdot 0)^{2}

9 (3 \cdot 0)^{2} = 0

9 (3 \cdot 0)^{2}

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

(3 \cdot 0)^{2}

使用法则

0 \cdot a = 0

= 0^{2}

使用法则

0^{a} = 0

= 0

= 9 \cdot 0

使用法则

0 \cdot a = 0

= 0

= 81 - 0

数字相减:

81 - 0 = 81

= 81

因式分解数字:

81 = 9^{2}

= 9^{2}

使用根式运算法则:

n a^{n} = a

9^{2} = 9

= 9

= 9

两侧不相等

\Rightarrow 假

流行的例子

证明 (1+sec(x))/(csc(x))=sin(x)+tan(x)

p ro v e \frac{1 + sec ( x )}{csc ( x )} = sin (x) + tan (x)

证明 (cot(x))(sec(x))(sin(x))=1

p ro v e (cot (x)) (sec (x)) (sin (x)) = 1

证明 (cos(a))/(1-sin(a))-tan(a)=sec(a)

p ro v e \frac{cos ( a )}{1 - sin ( a )} - tan (a) = sec (a)

证明 tan(θ/2)+cot(θ/2)=2csc(θ)

p ro v e tan (\frac{θ}{2}) + cot (\frac{θ}{2}) = 2 csc (θ)

证明 sin^2(2θ)=4sin^2(θ)cos^2(θ)

p ro v e sin^{2} (2 θ) = 4 sin^{2} (θ) cos^{2} (θ)