Question

If sin A = 4/5 then Cos A= help me in this sum please ​

Answer 1

Answer:

cosA=3/5

Step-by-step explanation:

sinA=4/5

make a triangle with hypotenuse 5x and side opp. to angle theta=4

by Pythagoras theorem

3rd side=√25-16

=√9

=3

therefore,

cos (theta)=adjacent side/hypotenuse

=3/5

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Answer 2

EXPLANATION.

⇒ sin(A) = 4/5.

As we know that,

⇒ sinθ = Perpendicular/Hypotenuse.

⇒ sinθ = p/h = 4/5.

By using Pythagoras theorem, we get.

⇒ H² = P² + B².

Hypotenuse > Perpendicular > Base.

Using this formula in the equation, we get.

⇒ (5)² = (4)² + B².

⇒ 25 = 16 + B².

⇒ 25 - 16 = B².

⇒ 9 = B².

⇒ B = √9.

⇒ B = 3.

⇒ cosθ = Base/Hypotenuse.

⇒ cos(A) = 3/5.

                                                                                                                       

MORE INFORMATION.

(1) sin²θ + cos²θ = 1.

(2) 1 + tan²θ = sec²θ.

(3) 1 + cot²θ = cosec²θ.