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