What is the minimum value of the function (-3\cos x)?
Answer and explanation
Correct answer: \(-3\)
Since \(\cos x\) lies between \(-1\) and \(1\), \(-3\cos x\) lies between \(-3\) and \(3\). When \(\cos x=1\), we get \(-3\cos x=-3\); hence the minimum value is \(-3\). The value \(3\) is the maximum, obtained when \(\cos x=-1\). Exam tip: multiplying a trigonometric function by a negative number reverses the order of its maximum and minimum values.
Frequently asked questions
What is the correct answer to this question?
\(-3\)
Why is this the correct answer?
Since \(\cos x\) lies between \(-1\) and \(1\), \(-3\cos x\) lies between \(-3\) and \(3\). When \(\cos x=1\), we get \(-3\cos x=-3\); hence the minimum value is \(-3\). The value \(3\) is the maximum, obtained when \(\cos x=-1\). Exam tip: multiplying a trigonometric function by a negative number reverses the order of its maximum and minimum values.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Trigonometric functions and their properties.
