The following groups are provided:

3、4、5; 5、 12、 13

7、24、25; 8、 15、 17

9、40、4 1; 1 1、60、6 1

12、35、37; 13、84、85

15、 1 12、 1 13; 16、63、65。 . . .

See the pattern? You can have as much as you want. . .

But many math teachers have been teaching all their lives.

I didn't get it. After a while, you will have confidence.

Step 2: Take a right triangle as an example. As long as they are similar,

The side length ratio of each triangle is

No matter the size, it will not change. Understand similarity and consistency.

Step 3: Use Pythagorean Theorem to calculate the edge-to-edge ratio at a special angle.

Three special angles: 30 degrees, 45 degrees and 60 degrees.

Then calculate sine = opposite side: hypotenuse.

Cosine = adjacent side: hypotenuse

Tangent = opposite side: adjacent side

Cotangent = adjacent edge: opposite edge

Practice the function values of some special angles, and then

Very useful.

Step 4: be familiar with the unit circle, quadrant, phase and amplitude.

The concept of frequency. Familiar with graphics.

Step 5: Learn to solve simple trigonometric equations.

Step 6: Learn how to combine product with difference and sum with difference.

Step 7: Learn the trigonometric inverse function.

Step 8: Input limit and calculus.

The above opinions are for your reference. Learning mainly depends on thinking, just figure it out.