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利用锐角三角函数解题时,一方面要注意锐角三角函数向线段比的转化;另一方面也可以利用等角的锐角三角函数,由已知三角形来了解未知三角形.这是锐角三角函数的两个重要的解题功能.一、锐角三角函数向线段比的转化例1如图1,在平面直角坐标系中,点A,B分别在x轴、y轴的正半轴上,OA=4,OB=3.过点A作DA⊥OA,点D在第一象限,点P在y轴负半轴上,OP=7.当∠PDB=90°
The use of acute trigonometric function to solve the problem, on the one hand should pay attention to acute angle trigonometric function to line segment ratio conversion; the other hand, you can also use the equilateral acute trigonometric function known triangles to understand the unknown triangle. This is acute trigonometric function of the two An important problem-solving function. A, acute trigonometric function to the line segment conversion Example 1 As shown in Figure 1, Cartesian coordinate system, the point A, B, respectively, in the positive x-axis and y-axis, OA = 4 , OB = 3, point A for DA ⊥ OA, point D in the first quadrant, point P on the negative y-axis, OP = 7. When ∠PDB = 90 °