For the graph of the function \(y=-\cos x\), what is the value of \(y\) when \(x=0\)?
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Answer and explanation
Correct answer: -1
Substituting \(x=0\) gives \(y=-\cos 0=-1\), since \(\cos 0=1\). Option B omits the negative sign and gives the value of \(\cos 0\), not \(-\cos 0\). Exam tip: evaluate the standard trigonometric value first, then apply any sign outside the function.
Frequently asked questions
What is the correct answer to this question?
-1
Why is this the correct answer?
Substituting \(x=0\) gives \(y=-\cos 0=-1\), since \(\cos 0=1\). Option B omits the negative sign and gives the value of \(\cos 0\), not \(-\cos 0\). Exam tip: evaluate the standard trigonometric value first, then apply any sign outside the function.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Domain, range, and graphs of trigonometric functions.
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