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If 5 Cos = 6 Sin ; Evaluate: (I) Tan θ (Ii) (12sin θ – 3 Cos θ)/(12 Sin θ + 3 Cos θ) - Mathematics

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Question

If 5 cos  = 6 sin ; evaluate:
(i) tan θ
(ii) `(12 sin θ – 3 cos θ)/(12 sin θ + 3 cos θ)`

Sum

Solution

5 cos θ = 6 sin θ

tan θ = `(5)/(6)`

Now
(i) tan θ = `(5)/(6)`

(ii) `(12 sin θ – 3 cos θ)/(12 sin θ + 3 cos θ) = ((12 sin θ)/cos θ – (3 cos θ)/cos θ)/((12 sin θ)/cos θ + (3 cos θ)/ cos θ)` 

= `( 12 tan θ – 3)/(12 tan θ + 3)`

= `(12(5/6)–3)/(12(5/6)+3)`

= `(42/6)/(78/6)`

= `(42)/(78)`

= `(7)/(13)`

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Chapter 22: Trigonometrical Ratios [Sine, Consine, Tangent of an Angle and their Reciprocals] - Exercise 22 (B) [Page 287]

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Selina Concise Mathematics [English] Class 9 ICSE
Chapter 22 Trigonometrical Ratios [Sine, Consine, Tangent of an Angle and their Reciprocals]
Exercise 22 (B) | Q 30 | Page 287
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