How many degrees does the minute hand of the clock rotate from 4 o'clock to coincide with the hour hand

How many degrees does the minute hand of the clock rotate from 4 o'clock to coincide with the hour hand

The minute hand turns 360 ° and the hour hand turns 30 °, that is, the minute hand turns 1 ° and the hour hand turns 1 / 12 °, that is to say, the minute hand turns 1 ° to catch up with the hour hand 11 / 12 ° and at four o'clock, the hour hand is 120 ° ahead of the minute hand. Then the minute hand turns 120 / (11 / 12) = 1440 / 11 ° and just catches up with the hour hand. At this time, the two are reunited, and the angle is 1440 / 11 = 130.9 °

Between 4 o'clock and 5 o'clock, when the minute hand of the clock rotates clockwise from 4 o'clock, how many degrees does the minute hand coincide with the hour hand?

The minute hand moves 6 ° every minute, and the hour hand moves 0.5 ° every minute to calculate their difference, but pay attention to the different starting points of the two. That is 6x = 120 + 0.5x = 120 / 5.5x = 240 / 11 minutes. After 240 / 11 minutes, the minute hand and the hour hand coincide, so the minute hand turns 240 / 11 * 6 = 1440 / 11 degrees

If the center of symmetry of the inverse function of F (x) = (x-a) / (x + a) is (1, - 1), then a =?

The center of symmetry of F (x) is (- 1,1)
f(x)=1-2a/(x+a)
When x = - 1, - 2A / (x + a) = 0
-2a/(-1+a)=0
A = 0 (1 round)