Question

96 points here, having to ask same question again - please help a brother out.

Answer 1

See attached pictures for answers

Answer 2

the equation is - tan2 x + sec2 x = 1.

Left hand side identity : - tan2 x + sec2 x.

Trigonometric function : tan x = sin x / cos x,

Reciprocal identity : sec x = 1/cos x.

- tan2 x + sec2 x = - (sin x/cos x)2 + (1/cos x)2

= - sin2 x/cos2 x + 1/cos2 x

= (1 - sin2 x)/cos2 x

Pythagorean identity : sin2 x + cos2 x = 1 .

= cos2 x / cos2 x

= 1