Posted by Sarah on .
Prove :cosxcosy= 2sin(x+y/2)sin(xy/2)
Prove: 2cot2tanx= 42sec^2x / tanx

Math 
Ajay bharti,
2Sinx
Posted by Sarah on .
Prove :cosxcosy= 2sin(x+y/2)sin(xy/2)
Prove: 2cot2tanx= 42sec^2x / tanx
2Sinx