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ICSEClass 10MathematicsTrigonometrical Identities01 Mark2024 Moderate

QQuestion

Statement (i): sin² θ + cos² θ = 1

Statement (ii): cosec² θ + cot² θ = 1

Which of the following is valid?

(a) Only (i)

(b) Only (ii)

(c) Both (i) and (ii)

(d) Neither (i) nor (ii)

Exam-ready answer • 01 Mark

Answer

(a) Only (i)

Explanation:

The fundamental trigonometric identity is:

sin² θ + cos² θ = 1

Therefore, Statement (i) is true.

Another identity is:

cosec² θ − cot² θ = 1

Statement (ii) uses a plus sign, so it is false.

Hence, only Statement (i) is valid.

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