KnowledgeBoat Logo

Mathematics

From the adjoining figure, find

(i) tan x°

(ii) x

(iii) cos x°

(iv) use sin x° to find y.

From the figure, find tan x° cos x°. Trigonometrical Ratios of Standard Angles, ML Aggarwal Understanding Mathematics Solutions ICSE Class 9.

Trigonometrical Ratios

27 Likes

Answer

(i) By formula,

tan x° = PerpendicularBase=ABBC=3\dfrac{\text{Perpendicular}}{\text{Base}} = \dfrac{AB}{BC} = \sqrt{3}.

Hence, tan x° = 3\sqrt{3}.

(ii) tan x° = 3\sqrt{3}

⇒ tan x° = tan 60°

⇒ x = 60.

Hence, x = 60.

(iii) Substituting value of x in cos x°, we get :

⇒ cos x° = cos 60°

⇒ cos x° = 12\dfrac{1}{2}.

Hence, cos x° = 12\dfrac{1}{2}.

(iv) Substituting value of x in sin x°, we get :

⇒ sin x° = sin 60° = 32\dfrac{\sqrt{3}}{2}.

By formula,

sin x°=PerpendicularHypotenuse32=ABAC32=3yy=2.\Rightarrow \text{sin x}\degree = \dfrac{\text{Perpendicular}}{\text{Hypotenuse}} \\[1em] \Rightarrow \dfrac{\sqrt{3}}{2} = \dfrac{AB}{AC} \\[1em] \Rightarrow \dfrac{\sqrt{3}}{2} = \dfrac{\sqrt{3}}{y} \\[1em] \Rightarrow y = 2.

Hence, y = 2.

Answered By

18 Likes


Related Questions