Question

Help with trig! screenshot is attached

Answer 1

The statement is very abstruse for me-:(

Answer 2

I'm stuck :(

Answer 3

and so am I.

Answer 4

Darn!

Answer 5

@nelsonjedi

Answer 6

just two points: sec(a/2) = 1/cos(a/2) and 2*cos^2(a/2)-1 = cos(a)

Answer 7

2*cos^2(a/2)-1=cos(a) => sqrt(cos(a)+1/2) = cos (a/2) and so sec(a/2) = sqrt[1/(cos(a)+1/2)] = sqrt[2/cos(a)+1] so A is true.

Answer 8

the key points here is that you should know secant of an angle is equal to 1/cos of that angle, and cos of an angle A can be written as 2*cos^2(A/2)-1

Answer 9

Thanks so much for explaining it!