1. Can anyone show me how to prove.
Tan(2x)=2 tanx/1-tan^2x
2. Divide 4864 into three equal parts such that the second part is 5 times the first and the ratio to second part to third part is 3:4
3. A river loses water by 10 percent of the current amount each day. How many days will it be until less than half remains?
4. Solve for x:
1. x+1/3 + x+4/4 =2
2. 2x-1/3 + x+2/6 =1
3. x-1/5 - x +2/2 =9
4. 7x-1/8 - x+2/4 =3
5. Two circles touch each other externally. The sum of their areas is 130x22/7cm². If the difference between their centres is 14 cm then what is the radius of the smaller circle?