Question

If cos A 2/5 = , find the value of 4 + 4 tan2 A

Answer 1

= 4+4 of 2 of 2/5
= 8 of 4/5
= 32/5
= 6.4

Answer 2

Answer:

$4+4\tan^2A=25$

Step-by-step explanation:

Given : $\cos A=\frac{2}{5}$

To find : The value of $4+4\tan^2A$

Solution :

We know,

$\sec A=\frac{1}{\cos A}$

$\cos A=\frac{2}{5}$

$\sec A=\frac{5}{2}$

The expression is written as,

$4+4\tan^2A=4(1+\tan^2 A)$

$4+4\tan^2A=4(sec^2 A)$

$4+4\tan^2A=4\times (\frac{5}{2})^2$

$4+4\tan^2A=5\times 5$

$4+4\tan^2A=25$