(sinθ+cosθ)/(sinθ-cosθ)=7 হলে secθ এর মান কত?
Solution
Correct Answer: Option B
দেওয়া আছে, (sinθ+cosθ)/sinθ-cosθ)=7
or,(sinθ+cosθ+sinθ-cosθ)/(sinθ+cosθ-sinθ+cosθ)=(7+1)/(7-1)[যোজন-বিয়োজন করে]
or,2sinθ/2cosθ=8/6
or,tanθ=4/3
or,tan2θ=16/9
or,sec2θ-1=16/9
or,sec2θ=(16/9)+1
∴ secθ=√(25/9)=±5/3