Direct answer

Principal value branches, domain and range, properties and simplification of inverse trig expressions.

Principal value branches, domain and range, properties and simplification of inverse trig expressions.

Key ideas

Inverse Trigonometric Functions: what you must understand

  • sin⁻¹x has range [−π/2, π/2]; cos⁻¹x has [0, π]
  • sin⁻¹x + cos⁻¹x = π/2
  • sin(sin⁻¹x) = x always for x in [−1, 1]; sin⁻¹(sin x) = x only in the principal range
  • Convert all terms to one function before simplifying
Formula sheet

Must-know formulas for Inverse Trigonometric Functions

  • tan⁻¹x + tan⁻¹y = tan⁻¹((x + y)/(1 − xy)) for xy < 1
  • 2tan⁻¹x = sin⁻¹(2x/(1 + x²)) for |x| ≤ 1
  • tan⁻¹x + cot⁻¹x = π/2
  • sin⁻¹(−x) = −sin⁻¹x, cos⁻¹(−x) = π − cos⁻¹x
Print

One-page formula sheet

Printable Inverse Trigonometric Functions formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.

Avoid

Common mistakes students make

  • Ignoring principal ranges
  • Using sum formulas outside their conditions
  • Sign errors for negative arguments
For the exam

How this topic is asked in JEE

Appears regularly; quick marks. Usually one question. Principal value traps are the most common mistake.

Prerequisites: Trigonometry (Ratios, Identities, Equations).

NCERT map

Where Inverse Trigonometric Functions is in NCERT

Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.

ClassBookChapterSections JEE asks from
Class 12Mathematics Part IInverse Trigonometric FunctionsBasic Concepts (principal value branch); Properties of Inverse Trigonometric Functions; Graphs of Inverse Trigonometric Functions
JEE Advanced level

A JEE Advanced-level example on Inverse Trigonometric Functions

Question. If sin⁻¹(x) + sin⁻¹(y) + sin⁻¹(z) = 3π/2, find the value of x²y² + y²z² + z²x² + 2x²y²z².

Show solution
  1. The range of sin⁻¹(t) is [-π/2, π/2], so the maximum value is π/2 when t = 1.
  2. For three terms to add up to 3π/2, each must equal its maximum: sin⁻¹(x) = sin⁻¹(y) = sin⁻¹(z) = π/2.
  3. This gives x = y = z = 1.
  4. Substitute into the expression: x²y² + y²z² + z²x² + 2x²y²z² = 1 + 1 + 1 + 2 = 5.

Answer: 5

This example was solved twice independently and both solutions agree.

Free lectures

Best free lectures for Inverse Trigonometric Functions

Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.

FAQs

Frequently asked questions

Is Inverse Trigonometric Functions important for JEE Main 2027?

Appears regularly; quick marks. It is part of the official 'Trigonometry' unit in the JEE Main 2027 syllabus.

What are the most important formulas in Inverse Trigonometric Functions?

tan⁻¹x + tan⁻¹y = tan⁻¹((x + y)/(1 − xy)) for xy < 1; 2tan⁻¹x = sin⁻¹(2x/(1 + x²)) for |x| ≤ 1; tan⁻¹x + cot⁻¹x = π/2.

How should I study Inverse Trigonometric Functions for JEE?

Understand the key ideas from NCERT or one full lecture, learn the formula sheet, then solve 25–30 past JEE questions on the topic. Usually one question. Principal value traps are the most common mistake.

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