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The minimum value of sin2θ + cos2θ + sec2θ + 2cosec2θ + tan2θ 

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The minimum value of sin2θ + cos2θ + sec2θ + 2cosec2θ + tan2θ 


1). 5
2). 7
3). 8
4). 9


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sin2θ + cos2θ + sec2θ + 2cosec2θ + tan2θ

(? sin2θ + cos2θ = 1)

= 1 + sec2θ + 2cosec2θ + tan2θ

= 1 + tan2θ + sec2θ + 2cosec2θ

= 2sec2θ + 2cosec2θ

$(= \;\frac{2}{{{{\sin }^2}\theta }}\; + \;\frac{2}{{{{\cos }^2}\theta }}\; = \;\frac{{2\left( {{{\cos }^2}\theta \; + \;{{\sin }^2}\theta } \right)}}{{{{\cos }^2}\theta .{{\sin }^2}\theta }}\; = \;\frac{2}{{{{\left( {\cos \theta .\sin \theta } \right)}^2}}})$

The given expression will be minimum when the denominator will be maximum.

Maxmium value of (sinθ.cosθ)2 = ¼

Minimum value of $(\frac{2}{{{{\left( {\cos \theta .\sin \theta } \right)}^2}}}\; = \;\frac{2}{{\frac{1}{4}}}\; = \;8)$

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