(1) tangent triangle culvert: 1+ tan? = 1/cos half angle tan (θ/2) = (1-cos θ)/sin θ = sin θ/(1+cos θ), which is common in mechanics.

(2) Similarity+cosine theorem is common in mechanics.

(3) Sequential method (rare)

(4) Space coordinate vector: If a cube is given, three charges are hung on any three vertices, and the electric field at a certain point is the same as that at a certain point, the space coordinate superposition of a single field vector can be written (especially fast), which is exactly what the physics teacher lacks, so it is not easy to find this method from the teacher.

(5) derivative? The teacher doesn't need it, because it has long been forgotten. For simple kinematic equations, velocity and acceleration can be obtained by derivation, and electromagnetic induction is very useful. What are sine and cosine magnetic fluxes?

(6) The mean value theorem that physics teachers often forget is not easy to find from teachers. One of the questions I saved is

(7) Knowledge of tangent properties and conclusions of circles in plane geometry (commonly used in magnetic fields). (Search for information by yourself)

(8) Consolidate the physical foundation, try to solve more than one problem, and try to find the optimal solution in daily practice (sometimes the answer is particularly disgusting, not as good as you think)