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Subject. Mathematics (F.2). PROJECT TITLE. Trigonometric Ratios. Target Audience. F.2 Students. How Slides are going to be used ?. The Slide are going to be used during lesson. System Requirement. A computer with the following software installed Power Point 97/2000.
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Subject Mathematics (F.2)
PROJECT TITLE Trigonometric Ratios
Target Audience F.2 Students
How Slides are going to be used ? The Slide are going to be used during lesson
System Requirement A computer with the following software installed Power Point 97/2000
Trigonometric Ratios Contents • Introduction to Trigonometric Ratios • Unit Circle • Adjacent , opposite side and hypotenuse of a right angle triangle. • Three types trigonometric ratios • Conclusion
Introduction Trigonometric Ratios Trigonometry (三角幾何) means “Triangle” and “Measurement” In F.2 we concentrated on right angle triangles.
Y 1 units x Unit Circle A Unit Circle Is a Circle With Radius Equals to 1 Unit.(We Always Choose Origin As Its centre)
Adjacent , Opposite Side and Hypotenuse of a Right Angle Triangle.
Opposite side hypotenuse Adjacent side
hypotenuse Adjacent side Opposite side
Three Types Trigonometric Ratios • There are 3 kinds of trigonometric ratios we will learn. • sine ratio • cosine ratio • tangent ratio
Sine Ratios Definition of Sine Ratio. Application of Sine Ratio.
Opposite sides Definition of Sine Ratio. 1 If the hypotenuse equals to 1 Sin =
Opposite side hypotenuses Definition of Sine Ratio. For any right-angled triangle Sin =
4 7 Exercise 1 In the figure, find sin Opposite Side Sin = hypotenuses 4 = 7 = 34.85 (corr to 2 d.p.)
Exercise 2 In the figure, find y y Opposite Side Sin35 = hypotenuses 35° 11 y Sin35 = 11 y = 11 sin35 y = 6.31 (corr to 2.d.p.)
Cosine Ratios • Definition of Cosine. • Relation of Cosine to the sides of right angle triangle.
Adjacent Side Definition of Cosine Ratio. 1 If the hypotenuse equals to 1 Cos =
Adjacent Side hypotenuses Definition of Cosine Ratio. For any right-angled triangle Cos =
Exercise 3 3 In the figure, find cos adjacent Side cos = 8 hypotenuses 3 = 8 = 67.98 (corr to 2 d.p.)
Exercise 4 In the figure, find x 6 Adjacent Side Cos 42 = 42° hypotenuses x 6 Cos 42 = x 6 x = Cos 42 x = 8.07 (corr to 2.d.p.)
Tangent Ratios • Definition of Tangent. • Relation of Tangent to the sides of right angle triangle.
Opposite Side Adjacent Side Definition of Tangent Ratio. For any right-angled triangle tan =
Exercise 5 3 In the figure, find tan Opposite side 5 tan = adjacent Side 3 = 5 = 78.69 (corr to 2 d.p.)
Exercise 6 In the figure, find z z 22 Opposite side tan 22 = adjacent Side 5 5 tan 22 = z 5 z = tan 22 z = 12.38 (corr to 2 d.p.)
Conclusion Make Sure that the triangle is right-angled