r+r*(-cos(t))=2r+2r*(-cos(t))
find x
x^2/3 =64
sin^2x + 0.5tanx = 1
In a certain part of America , 1/3 of the population
1+2\*5/3+6/4*2
1/2*3*2
x-3y=6
0.2*10^2
how to do 75.5+0.4
10^20 /10^18
