What is the minimum value of \(\cos^2 \theta\)?
Answer and explanation
Correct answer: \(0\)
For every real \(\theta\), \(-1 \leq \cos\theta \leq 1\). Hence, \(\cos^2\theta\) lies in the interval from \(0\) to \(1\). When \(\cos\theta=0\), for example at \(\theta=\frac{\pi}{2}\), we get \(\cos^2\theta=0\). Therefore, the minimum value is \(0\). The value \(1\) is the maximum, not the minimum. Exam tip: the square of a real number cannot be negative.
Frequently asked questions
What is the correct answer to this question?
\(0\)
Why is this the correct answer?
For every real \(\theta\), \(-1 \leq \cos\theta \leq 1\). Hence, \(\cos^2\theta\) lies in the interval from \(0\) to \(1\). When \(\cos\theta=0\), for example at \(\theta=\frac{\pi}{2}\), we get \(\cos^2\theta=0\). Therefore, the minimum value is \(0\). The value \(1\) is the maximum, not the minimum. Exam tip: the square of a real number cannot be negative.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Trigonometric functions and their properties.
