Question

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

Answer 1

cosA=2/5
sinaA=√{1-(2/5)^2}
=√1-4/25
=√21/25=(√21)/5
tanA=sinA/cosA
=(√21)/5÷2/5
=(√21)/2

LHS
4+4tan^2A
=4+4*{(√21)/2}^2
=4+4*21/4
=4+21
=25

Answer 2

Answer:

25

Step-by-step explanation:

cosA=2/5

sinaA=√{1-(2/5)^2}

=√1-4/25

=√21/25=(√21)/5

tanA=sinA/cosA

=(√21)/5÷2/5

=(√21)/2

LHS

4+4tan^2A

=4+4x{(√21)/2}^2

=4+4x21/4

=4+21

=25