Foundation
Mathematics Foundation
Introduction to Trigonometry
Question

If 3 cot θ = 4 then (5sinθ+3cosθ)(5sinθ3cosθ)=?

9

13

3

19

JEE Advance
College PredictorLive

Know your College Admission Chances Based on your Rank/Percentile, Category and Home State.

Get your JEE Main Personalised Report with Top Predicted Colleges in JoSA

Solution

Given 3 cot θ = 4, so cot θ = 4/3. Therefore, cos θ/sin θ = 4/3. Let sin θ = 3k and cos θ = 4k for some constant k.

Substitute into the expression: (5(3k)+3(4k))(5(3k)-3(4k))=15k+12k15k-12k=27k3k=9

Final Answer: 9