Q. 2 E

Let us show that:sec70°sin20° + cos20°cosec70° = 2

Given, sec70°sin20° + cos20°cosec70° = 2

Need to prove the given equation as two

we know that sec(90 - θ) = cosecθ and cosec(90 - θ) = secθ

sec70° = sec(90 - 20)°

= cosec20° - - - eq (1)

And cosec70° = cosec(90 - 20)

= sec20° - - - - - eq(2)

Substitute eq(1) and eq(2) in the given equation

cosec20°sin20° + cos20°sec20° = 2

[ and ]

= 2

2 = 2

Hence, proved

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