Graphs, Domain and Range of Trig Func

Duration: 34 min

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Module outline

General Intelligence & Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Analytical Reasoning (Counting Figures Reasoning), Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Syllogisms, Puzzle Solving (Puzzles), Venn Diagram, Clerical Aptitude, Verbal Classification
General Awareness: Polity, Physics, Biology, Chemistry, History, Geography, Indian Economy, Environment, GK- Current Affairs, Static General Knowledge
Quantitative Aptitude: Ratio and Proportion (Ratios), Data Interpretation, Mixture and Alligation, Number System, Speed Time and Distance, Percentage, Average, Arithmetic, Simple Interest and Compound Interest, Profit and Loss, Partnership, Time and Work, Algebra, Mensuration and Geometry, Trigonometry, Linear Algebra
English Comprehension: Vocabulary, Noun, Subject Verb Agreement (Verb Noun Agreement), Adjectives, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Pronoun, Preposition, Articles, Adverb, Interjection, Conjunction, Modals, Determiner, Active Passive Voice (Voice), Direct and Indirect Speech, Verbal Analogy (Word Based Analogy), Cloze Test (Cloze Passage), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks)
MOCK TEST:

AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive lecture on the domain, range, and graphs of the six primary trigonometric functions. The instructor begins by introducing the topic and then systematically analyzes each function: sine, cosine, tangent, cotangent, secant, and cosecant. For each function, the video displays its algebraic definition, constructs its graph on a Cartesian coordinate system, and explicitly states its domain and range. The graphs are drawn with key points and asymptotes, and the periodic nature of the functions is highlighted. The lecture also includes a table of standard trigonometric values and a final note summarizing that all trigonometric functions are periodic.

Chapters

0:00 – 2:00 00:00-02:00
The video opens with a title slide: 'Domain, Range and Graph of Trigonometric functions :'. The first function, f(x) = sin x, is introduced. The instructor begins to set up a Cartesian coordinate system, drawing the x and y axes, and labels the x-axis with key angles in radians (π/2, π, 3π/2, 2π) and the y-axis with the value 1. The function is written as y = sin x.
2:00 – 5:00 02:00-05:00
The instructor draws the graph of y = sin x, starting from the origin and creating a smooth, periodic wave. The graph is shown to pass through key points like (0,0), (π/2,1), (π,0), (3π/2,-1), and (2π,0). The instructor then labels the domain as (-∞, ∞) and the range as [-1, 1]. The periodicity is identified as 2π, with a visual arrow indicating the length of one period.
5:00 – 10:00 05:00-10:00
The video transitions to the second function, f(x) = cos x. The instructor draws the graph of y = cos x, which is a sine wave shifted to the left by π/2. The graph is shown to pass through (0,1), (π/2,0), (π,-1), (3π/2,0), and (2π,1). The domain is stated as R (all real numbers), the range as [-1, 1], and the periodicity as 2π.
10:00 – 15:00 10:00-15:00
The third function, f(x) = tan x, is introduced. The instructor writes the definition tan x = sin x / cos x and notes that cos x ≠ 0. The graph is drawn with vertical asymptotes at x = (2n+1)π/2, where n is an integer. The graph consists of repeating segments between the asymptotes, passing through the origin. The domain is given as R - {(2n+1)π/2}, the range as R, and the periodicity as π.
15:00 – 20:00 15:00-20:00
The fourth function, f(x) = cot x, is presented. The definition cot x = cos x / sin x is written, with the condition sin x ≠ 0. The graph is drawn with vertical asymptotes at x = nπ, where n is an integer. The graph consists of repeating segments between the asymptotes, passing through the origin. The domain is R - {nπ}, the range is R, and the periodicity is π.
20:00 – 25:00 20:00-25:00
The fifth function, f(x) = cosec x, is introduced with the definition cosec x = 1 / sin x, where sin x ≠ 0. The graph is drawn with vertical asymptotes at x = nπ. The graph consists of U-shaped curves above and below the x-axis, with peaks at y=1 and troughs at y=-1. The domain is R - {nπ}, the range is (-∞, -1] ∪ [1, ∞), and the periodicity is 2π.
25:00 – 30:00 25:00-30:00
The sixth function, f(x) = sec x, is presented with the definition sec x = 1 / cos x, where cos x ≠ 0. The graph is drawn with vertical asymptotes at x = (2n+1)π/2. The graph consists of U-shaped curves above and below the x-axis, with peaks at y=1 and troughs at y=-1. The domain is R - {(2n+1)π/2}, the range is (-∞, -1] ∪ [1, ∞), and the periodicity is 2π.
30:00 – 33:44 30:00-33:44
The video concludes with a 'Note' slide. The instructor writes the statement: 'All trig. functions are periodic :'. This summarizes the key property of the functions discussed, reinforcing that their graphs repeat at regular intervals.

The video systematically presents a complete analysis of the six primary trigonometric functions. It follows a consistent structure for each function: definition, graph construction, and determination of domain, range, and periodicity. The visual method of drawing the graphs on a coordinate plane, highlighting key points and asymptotes, provides a clear understanding of their behavior. The lecture effectively uses the unit circle concept (implied by the use of radians and standard values) to explain the functions. The final note serves as a powerful summary, emphasizing the fundamental periodic nature of all trigonometric functions, which is a core concept in trigonometry.