1.

The value of sin2 θ cos2 θ ( sec2 θ + cosec2 θ) is(a) 2 (b) 4 (c) 1 (d) 3

Answer»

(c) 1

sin2 θ cos2 θ (sec2 θ + cosec2 θ)

= sin2 θ cos2 θ \(\bigg(\frac{1}{cos^2\,\theta}+\frac{1}{sin^2\,\theta}\bigg)\)

 = sin2 θ cos2 θ \(\bigg(\frac{sin^2\,\theta\,+\,cos^2\,\theta}{cos^2\,\theta\,sin^2\,\theta}\bigg)\)

= sin2 θ + cos2 θ = 1



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