(secθ+tanθ)=7/5 হলে, (secθ-tanθ) এর মান কত ?
Solution
Correct Answer: Option A
দেওয়া আছে,(secθ+tanθ)=7/5
or,1/(secθ+tanθ)=1/(7/5)
[since, sec2θ-tan2θ=1 এটা সুত্র]
or,(sec2θ-tan2θ)/(secθ+tanθ)=5/7
or,{(secθ+tanθ)(secθ-tanθ)}/(secθ+tanθ)=5/7
∴(secθ-tanθ)=5/7