Question

if Cos A = to 2 by 5 then find the value of 4 + 4tansquare A

Answer 1

Cos a=2/5=>sec a =1/cos a =5/2
Now,4+4tan^2 a=4(1+tan^2 a)
=4(sec^2 a)=4(25/4)=25.
Hope it helps