Unless there are some special angles in junior high school, you won't encounter the problem of "knowing the trigonometric function value of an angle and finding this angle"

After high school, especially in mathematics, such problems are very common, so people came up with the method of using inverse trigonometric function.

For example,

TanA=2.4, then A=arctan2.4.

CosA=0.3, then A=arccos0.3.

SinA=-0.4, then A=arcsin(-0.4)

Wait a minute.

As for those angles, which are more or less equal, because they are not special angles, we can only resort to calculation tools, such as calculators.

By the way, even if those values are calculated by a calculator, generally speaking, they are not angles but radians.

1 radian is approximately equal to 57.3 degrees.

Arctangent 2.4≈ 1. 176 radian ≈ 67.38.

Arccos0.3≈ 1.266 radian ≈ 72.54.

Arcane (-0.4)≈-0.4 12 radian ≈-23.58.