Trigonometric function fast memory formula Trigonometric function is a function, and quadrant symbols are marked. Function image unit circle, periodic parity increase and decrease.
The same angle relation is very important, and both simplification and proof are needed. At the vertex of the regular hexagon, cut the chord from top to bottom;
Write the number 1 in the middle to connect the vertex triangles. The sum of the squares of the downward triangle, the reciprocal relationship is diagonal,
Any function of a vertex is equal to the division of the last two. The inductive formula is good, negative is positive and then big and small,
It is easy to look up the table by turning it into an acute angle, and it is essential to simplify the proof. Half of the integer multiple of two, odd complementary pairs remain unchanged,
The latter is regarded as an acute angle, and the sign is judged as the original function. The cosine of the sum of two angles is converted into a single angle, which is convenient for evaluation.
Cosine product minus sine product, angular deformation formula. Sum and difference products must have the same name, and the complementary angle must be renamed.
The calculation proves that the angle is the first, pay attention to the name of the structural function, the basic quantity remains unchanged, and it changes from complexity to simplicity.
Guided by the principle of reverse order, the product of rising power and falling power and difference. The proof of conditional equality, the idea of equation points out the direction.
Universal formula is unusual, rational formula is ahead. The formula is used in the right and wrong direction, and the deformation is used skillfully;
Add cosine to think of cosine, subtract cosine to think of sine, raise the power by half, and raise the power by one norm;
The inverse function of trigonometric function is essentially to find the angle, first to find the value of trigonometric function, and then to determine the range of angle value;
Using right triangle, the image is intuitive and easy to rename. The equation of a simple triangle is reduced to the simplest solution set.
Symbolic judgment formula is complete, S, T, C, positive. The meaning of these five-word formulas is: the four trigonometric functions at any angle in the first quadrant are "+"; In the second quadrant, only the sine is "+",and the rest are "-"; Only the tangent in the third quadrant is "+",and the others are "-"; In the fourth quadrant, only cosine is "+",others are "-".
It can also be understood that the included angle of one, two, three and four fingers is in a quadrant. All sine, sine, tangent and cosine refer to the names in which the trigonometric function in the corresponding quadrant is positive. Everything not mentioned in the formula is negative.
"ASTC" is anti-Z, which means that "all", "sin", "tan" and "cos" are trigonometric functions, corresponding to the quadrant occupied by the letter Z in reverse.
Another formula: sine is one, two, one, three, cosine is one, and four are closely connected and positive.