Answer:
Adnan is incorrect because cosx and sin(90 - x) are always equivalent in any right triangle ⇒ first answer
Step-by-step explanation:
In any right triangle there are two acute angles sum of them is 90°
∴ If one of them x°, then the other is (90 - x)°
∵ cos x = adjacent/hypotenuse
∵ sin(90 - x) = opposite/hypotenuse
∵ The opposite of ∠(90 - x) is the adjacent of ∠x
∴ cosx = sin(90 - x)
