Write the first trigonometric function in terms of the second for θ in the given quadrant.
sec θ, sin θ; θ in quadrant i

This is how to answer this question: sec(θ) = 1 / sin(90−θ)

sec(θ) = 1 / cos(θ)
and
sin(θ) = cos(90−θ)

by the complementary angle rule
cos(θ)=sin(90−θ)

so use this to express
sec(θ)

So this will give us,
sec(θ) = 1 / cos(θ)
sec(θ) = 1 / sin(90−θ)

Hope this helps answer your question.

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