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If 5tanθ = 12, find the value of 2 sin θ − 3 cos θ 4 sin θ − 9 cos θ - Mathematics

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Question

If 5tanθ = 12, find the value of `(2sinθ - 3cosθ)/(4sinθ - 9cosθ)`.

Sum

Solution

5tanθ = 12

⇒ tanθ = `(12)/(5) = "Perpendicular"/"Base"`

Hypotenuse 
= `sqrt(("Perpendicular")^2 + ("Base")^2`
= `sqrt((12)^2 + (5)^2`
= `sqrt(144 + 25)`
= `sqrt(169)`
= 13
sinθ = `"Perpendicular"/"Hypotenuse" = (12)/(13)`, cosθ = `"Base"/"Hypotenuse" = (5)/(13)`

⇒ `(2sinθ - 3cosθ)/(4sinθ - 9cosθ)`

= `(2 xx 12/13 - 3 xx 5/13)/(4 xx 12/13 - 9 xx 5/13)`

= `(24 - 15)/(48 - 45)`

= `(9)/(3)`
= 3.

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Reciprocal Relations
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Chapter 26: Trigonometrical Ratios - Exercise 26.1

APPEARS IN

Frank Mathematics [English] Class 9 ICSE
Chapter 26 Trigonometrical Ratios
Exercise 26.1 | Q 28
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