How do you simplify cscX+cotX=sinX1+cosX?

1 Answer
Mar 22, 2016

This is not a valid identity.

Explanation:

We can prove this is invalid by using a test value of x=π4:

csc(π4)+cot(π4)sin(π4)1+cos(π4)

2+1121+12

2+112(1+12)

2+112+1

In fact, as we can might see is happening here, these functions are actually reciprocals of one another: they only intersect when their values equal 1 or 1.

We can also prove these are not equal by attempting to simplify the functions:

cscx+cotxsinx1+cosx

1sinx+cosxsinxsinx1+cosx

1+cosxsinxsinx1+cosx

Indeed, these functions are reciprocals of one another so the identity is invalid.