If \(\sec x-\tan x=\frac{1}{4}\), what is the value of (\sec x+\tan x)?
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Answer and explanation
Correct answer: 4
Using the identity \(\sec^2 x-\tan^2 x=1\), we get \((\sec x-\tan x)(\sec x+\tan x)=1\). Hence \(\frac{1}{4}(\sec x+\tan x)=1\), so \(\sec x+\tan x=4\). The option \(16\) may result from incorrectly squaring \(\frac{1}{4}\). Exam tip: rewrite \(\sec^2 x-\tan^2 x=1\) as a product in such questions.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
Using the identity \(\sec^2 x-\tan^2 x=1\), we get \((\sec x-\tan x)(\sec x+\tan x)=1\). Hence \(\frac{1}{4}(\sec x+\tan x)=1\), so \(\sec x+\tan x=4\). The option \(16\) may result from incorrectly squaring \(\frac{1}{4}\). Exam tip: rewrite \(\sec^2 x-\tan^2 x=1\) as a product in such questions.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Trigonometric functions and their properties.
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