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正切函数
正切函数如何用正弦函数和余弦函数来定义？
1. Introduction
Introduction
2. Two perspectives on the tangent function
Two perspectives on the tangent function
3. Properties of the tangent function
Properties of the tangent function
4. Using the tangent function in right triangles
Using the tangent function in right triangles
5. Summary
Summary
6. Tangent at pi over three
Using sine over cosine, what is the exact value of tan(pi/3)?
7. Setting up the river-width equations
Two sightings of a hilltop are taken 1000 feet apart at elevations of 25 and 19 degrees. Which pair of equations relates the height h and the nearer distance x?
8. River width from two sightings
Solving the two-sighting system gives x = 1000 tan(19)/(tan(25) - tan(19)). Using tan(19) = 0.3443 and tan(25) = 0.4663, what is x, to the nearest foot?
9. Ramp length and slope
A ramp rises 3 feet at a 4-degree angle. How long must the ramp be, and what is its slope?
10. A tangent ratio uses opposite over adjacent
For an acute angle in a right triangle, the tangent equals the opposite leg divided by the adjacent leg.