Question

if 2tanA=secA, then find 4 cot^A-8 tan^2A=

Answer 1

2TanA=secA.
2sinA/cosA= 1/cosA
Cancel cosA both sides,we get
2SinA=1
SinA=1/2
SinA=Sin30
This implies that A=30
4cot^2 30-8tan^2 30
4(root3)^2-8(1/root3)^2
4(3)-8(1/3)
12-8/3
36-8/3
28/3