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第1点三角函数的概念(★★★★)必做1如图1,以Ox为始边作角α与β(0<β<α<π),它们的终边分别与单位圆相交于点P,Q,已知点P的坐标为(-3/5,4/5).(1)求sin2α+cos2α+1/1+tanα的值;(2)若OP·OQ=0,求sin(α+β).破解思路(1)先根据三角函数的定义求出s inα,cosα,代入求三角函数式子的值.
The concept of the first point trigonometric function (★★★★) must be done as shown in Figure 1. Ox is used as the starting edge for angles α and β (0<β<α<π), and their end edges intersect with the unit circle respectively. Point P, Q, the coordinates of the known point P is (-3/5, 4/5). (1) find the value of sin2α+cos2α+1/1+tanα; (2) if OP·OQ=0, find Sin (α + β). Crack ideas (1) First find the s in α, cos α according to the definition of the trigonometric function, substituting for the value of the trigonometric function.