Question

if cosA =2/5 find the value of 4+4 tan2A
​

Answer 1

we know that, sec2a -tan2a=1
or,1/cosa-8 tan.2a=1
or, 5/2 -8 tan.2a=1
or, -8 tan .2a = 1+5/2
or, tan.2a= 4+8=12(ans)
please mark me as a braintest.