"Noioj" p7939

09: The Swollen stick

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Total time limit:

1000ms

Memory Limit:

65536kB

Describe

When the temperature of a fine stick of length l is increased by n degrees, it expands to the new length l ' = (1+n*c) *l, where C is the coefficient of thermal expansion.

When a thin stick is heated between two walls, it expands to form an arc of the bow, and the bow chord is the original position of the stick before it is heated.

Your task is to calculate the offset distance from the center of the stick.

Input

three nonnegative real numbers: The initial length of the stick (in millimeters), the temperature change (unit: degree), and the coefficient of thermal expansion of the material.
Ensure that the stick does not swell to 1.5 times times the original length.

Output

the offset distance (in millimeters) of the center of the stick, reserved to the third digit after the decimal point.

Sample input

1000 100 0.0001

1#include <iostream>2#include <cstdio>3#include <cmath>4 #definepi=3.141592635897935 using namespacestd;6 intMain ()7 {8     DoubleL,n,c,ll,left,mid,right;9scanf"%LF%LF%LF",&l,&n,&c);TenLl= (1+N*C) *l; Oneleft=0; ARight=asin (1.0); -      while(right-left>1e- -) -     { theMid= (Right+left)/2; -         if(Ll*sin (mid)/mid<=l) -right=mid; -         Else +left=mid; -     } +printf"%.3LF", l/2*tan (left/2)); A     return 0; at}

Online find the formula, because do not know that C + + sin is a radian calculation, and not radian system.

"Noioj" p7939