JEE Main 2020MathematicsTrigonometric Ratios & IdentitiesMediumMCQ

JEE Main 2020 — Trigonometric Ratios & Identities Question with Solution

JEE Main 2020 (09 Jan Shift 1)

Question

The value of cos3π8.cos3π8+sin3π8.sin3π8 is:

Choose an option

Show full solutionCorrect option: B
Correct answer
B122

Step-by-step explanation

⇒cos3π8cosπ2-π8+sin3π8sinπ2-π8

⇒cos3π8sinπ8+sin3π8cosπ8

⇒sinπ8cosπ8sin2π8+cos2π8

⇒12sinπ4

⇒122

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About this question

This is a previous-year question from JEE Main 2020, covering the Trigonometric Ratios & Identities chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.