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其他三角函数与恒等式（续）
另外 $3$ 个三角函数是什么，它们与余弦、正弦、正切函数有什么关系？
1. A few important identities
A few important identities
2. Summary
Summary
3. Sine's average rate expression
Using the sum identity, sin(a + h) expands to sin(a)cos(h) + cos(a)sin(h). If a = 0, what is the coefficient of sin(h)/h in the average rate expression?
4. The two limit terms
As h approaches 0, what do (cos h - 1)/h and (sin h)/h approach?
5. Five functions from one cosine
An angle in Quadrant II has cos(beta) = -12/13. What are sin(beta) and tan(beta)?
6. Transforming secant
For f(t) = 5 sec(t - pi/2) + 3, what are the period, asymptote locations and range?
7. The derivative of sine is cosine
Letting h approach zero in sine's average rate of change leaves cos(a), so the instantaneous rate of sine at a is cos(a).