In the formula of double radius intersection line, if the radii of the circumscribed circles of two mutually perpendicular convex polygons are R _ 1 and R _ 2, respectively, and the chord length of the two circumscribed circles is l, then the radius of the circumscribed sphere of the geometry formed by connecting the vertices of the two convex polygons is r = √ [r _12+r _ 2 2-(.
The strict concept of radian was put forward by the Swiss mathematician Euler (1707- 1783) in 1748. Euler is different from Aliyepito in that the radius is 1 unit, so the arc length of the semicircle is π, and the sine value at this time is 0, so it is recorded as sinπ=0. Similarly, the arc length of the circumference of 1/4 is π/2, and the sine at this time is 1, so it is recorded as sin (π/2) = 6544. Thus, the central angles of semicircle and 1/4 arc expressed by π and π/2 respectively are established. Other angles can also be analogized.
Application of the formula of double radius single intersection line: Let a=3 and n=5, and these two numbers are coprime. Among the positive integers less than 5, there are 1, 2, 3, 4, so φ(5)=4 (see Euler Function for details). Calculation: A {φ (n)} = 3 4 = 81,while 81= 80+1ξ1(mod 5). This is consistent with the theorem.