KnowledgeBoat Logo

Mathematics

If sin A = 12\dfrac{1}{2}, then the value of cot A is

  1. 3\sqrt{3}

  2. 13\dfrac{1}{\sqrt{3}}

  3. 32\dfrac{\sqrt{3}}{2}

  4. 1

Trigonometrical Ratios

4 Likes

Answer

Let ABC be a right angle triangle with ∠B = 90°.

If sin A = 1/2, then the value of cot A is? Trigonometrical Ratios, ML Aggarwal Understanding Mathematics Solutions ICSE Class 9.

By formula,

sin A = PerpendicularHypotenuse\dfrac{\text{Perpendicular}}{\text{Hypotenuse}}

Substituting values we get :

12=BCAC\Rightarrow \dfrac{1}{2} = \dfrac{BC}{AC}

Let BC = x and AC = 2x.

In right angle triangle ABC,

⇒ AC2 = AB2 + BC2

⇒ (2x)2 = AB2 + (x)2

⇒ 4x2 = AB2 + x2

⇒ AB2 = 3x2

⇒ AB = 3x2=3x\sqrt{3x^2} = \sqrt{3}x.

By formula,

cot A = BasePerpendicular=ABBC=3xx=3\dfrac{\text{Base}}{\text{Perpendicular}} = \dfrac{AB}{BC} = \dfrac{\sqrt{3}x}{x} = \sqrt{3}.

Hence, Option 1 is the correct option.

Answered By

2 Likes


Related Questions