Question

Please help me with this question!!!!!

Answer 1

Answer:

7/25

Step-by-step explanation:

θ lies in quadrant ii

so 2θ lies in quadrant iv

csc θ=5/3

sin θ=3/5 (sin θ=1/csc θ)

[cos(α+β)=cosαcosβ-sinαsinβ]

cos (2θ)=cos(θ+θ)=cos θ cos θ-sin θ sin θ=cos² θ-sin ²θ=1-sin²θ-sin²θ=1-2sin²θ

=1-2 (3/5)²

=1-2(9/25)

=1-18/25

=(25-18)/25

=7/25