Question

seca=5/4 evaluate sina/seca
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Answer 1

Answer

= (3/4)/ (5/4)²

= 12/25

Step-by-step explanation:

Let's take a triangle ABC right angled at B,

Now sec a = Hypotenuse/ Base = AC/AB = 5/4

Using Pythagoras theorem,

H² = P² + B²

P² = H² - B²

P² = 25 - 16

P = √9 = 3

so BC = 3

now tan a = Perpendicular/Base = BC/AB

tan a = 3/4

and 1+ tan²a = sec²a

putting values we get,

tan a/(1+tan²a)

=tan a / (sec²a)

= (3/4)/ (5/4)²

= 12/25