"Calculation of Acute Angle Trigonometric Functions" PPT courseware

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"Calculation of Acute Angle Trigonometric Functions" PPT courseware

1. To use a calculator to find the value of an acute angle trigonometric function, generally press the trigonometric function name key first, then enter the degree, use the "degrees, minutes and seconds" key to distinguish the degree unit, and finally press the = key. For example: use a calculator to find the value of cos 10°, The key sequence is: ON cos1 0 =,

The displayed result is approximately ________.

2. If you know the value of the trigonometric function and use a calculator to find the degree of an acute angle, you should first press the second function key 2nd, then press the trigonometric function name key, then enter the value of the trigonometric function, and finally press = to make the result accurate as required, for example: known :tan α=3.9852, use the calculator to find the degree of acute angle α (accurate to 1″), the key sequence is ON 2nd tan -1 3 • 9 8 5 2 =, the displayed result is ________, so acute angle α≈________.

1. (3 points) Use a calculator to find the value of sin 24°37′18″,

The following key sequence is correct ()

A.sin 2 4 DMS 3 7 DMS 1 8 DMS =

B.2 4 DMS 3 7 DMS 1 8 DMS sin =

C.2nd sin 2 4 DMS 1 8 DMS =

D.sin 24DMS37DMS18DMS2nd＝

2. (3 points) Use a calculator to find (accurate to 0.0001):

(1)sin 5°12′≈________;

(2)cos 18°40′≈________;

(3)tan 18°36′≈________．

3． (3 points) Use a calculator to find the values ​​of sin 28°, cos 27°, and tan 26°. Their magnitude relationship is ()

A． tan 26°＜cos 27°＜sin 28°

B. tan 26°＜sin 28°＜cos 27°

C． sin 28°＜tan 26°＜cos 27°

D． cos 27°＜sin 28°＜tan 26°

【Error-prone Inventory】

[Example] Calculation: sin 248°+sin 242°-tan 44°•tan 45°•tan 46°=________.

[Wrong solution] Original formula = sin 248° + sin 242° - tan 44°·tan 46°.

[Error cause analysis] The wrong solution has not been solved yet, and you can continue to solve it. Because 48° + 42° = 90°, 44° + 46° = 90°, so there are: sin 42° = cos 48°, sin 248° + cos 248° = 1, tan 44°·tan 46° = 1.

19. (10 points) After the earthquake, a professional search and rescue team drove to the disaster area for rescue. As shown in the picture, the car is driving north on a north-south road. When it is at location A, the on-board GPS (Global Positioning System) shows that village C is 26° north-west, and the car is traveling at a speed of 35 km/h. Arriving at point B in 2 hours, the GPS shows that the village is in the direction of 52° north by west.

(1) Find the distance from B to village C;

(2) Find the distance from village C to the road. (The result is accurate to 0.1km/h) Reference data: sin 26°≈0.4384, cos 26°≈0.8988, sin 52°≈0.7880, cos 52°≈0.6157)

70 km, 55.2 km

【Integrated use】

20. (16 points) Explore the relationship between the sine, cosine and tangent of the acute angle α.

(1) Fill in the table based on the trigonometric function values ​​of angles 30°, 45°, and 60°.

Compare the values ​​of sin α/cos α and tan α at the same acute angle. What guesses can you draw from the comparison results?

(2) Use a calculator to calculate and fill the results directly into the table (the results are accurate to 0.000 1)

Compare the values ​​in the table. Does it verify your hypothesis?

(3) Please use a right triangle to prove your conjecture.

Keywords: Teaching courseware for the calculation of acute-angle trigonometric functions, download the ninth-grade mathematics PPT courseware for the first volume of the Hebei Education Edition, download the ninth-grade mathematics slide courseware, download the PPT courseware for the calculation of acute-angle trigonometric functions, .PPT format;

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Update Time: 2024-07-01

This template belongs to Mathematics courseware Hebei Education Edition Ninth Grade Mathematics Volume 1 industry PPT template

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