As everyone knows.
The sine value, sinθ, is equal to the opposite side c divided by the hypotenuse a; the tangent value, tanθ, is equal to the opposite side c divided by the adjacent side b.
Xu Yun drew a right triangle with a very small angle, probably only a few degrees:
"But once the angle θ gets extremely small, the adjacent side b and the hypotenuse a become almost identical."
"At this point, we can approximate a and b as equal, that is, a≈b."
Then he wrote on the paper:
[So we have c/b≈c/a, that is, tanθ≈sinθ.]
[The earlier equation can be written as F= T·tan(θ+Δθ)-T·tanθ=μ·Δxa∂²f/∂t².]
"Wait a minute."
Seeing this sentence, Faraday suddenly furrowed his brow and interrupted Xu Yun.
Obviously.
He was already showing signs of lagging behind:
"Luo Feng, what's the point of substituting tanθ for sinθ?"
Xu Yun glanced at Wheat, and Wheat immediately caught on:
