2025 HSC Mathematics Extension 1
Question 11(d):
Inverse trigonometric functions
Sketch with its domain and range.
How to recognise this question
Question type: inverse trigonometric functions
- The command and notation point to inverse trigonometric functions.
- The requested response is a sketch.
How to handle it: use the restricted domain and range that make the inverse function single-valued.
Watch out: Do not select a formula until its domain, interval, sign and units match the question.
Step-by-step answer
- For , require , so the domain is .
- The inverse-cosine range is .
- Plot , and , then join them with a decreasing curve.
Common mistake: choosing a familiar formula before checking that its conditions, signs, interval and units match this question.
The paper records 2 total marks for this group. Where the official marking guide provides useful partial-credit criteria, those criteria are stated in the steps above.
Try your hand at it again by answering these questions
Question 1
Sketch , stating its domain, range and three key points.
Question 2
Evaluate .
Question 3
Differentiate and find .