Correct option is A
Given:
cosecα=2
Formula used:
cosecα=sinα1
sinα=1/2
sin2α+cos2α=1
cosα=1−sin2α
Solution:
sinα=21,sosin2α=21
cos2α=1−21=21
cosec2α+cot2α2sin2α+3cosα
First, calculate the numerator:
Numerator = 2sin2α+3cos2α
Numerator = 2×21+3×21
Numerator = 1+23=2.5
Now, calculate the denominator:
Denominator = cosec2α+cot2α
We know cosecα=2
cosec2α=(2)2=2
cotα=sinαcosα=2121=1
cot2α=1
Denominator = 2 + 1 = 3
Finally, the expression becomes:
Result=32.5=65