when i first learnt separation of variables one teacher taught me to substitute in the conditions as lower limits whereas another teacher taught me to use arbitrary constants and substitute in the conditions to solve for these constants

which method is more widely used?

Question

when i first learnt separation of variables one teacher taught me to substitute in the conditions as lower limits whereas another teacher taught me to use arbitrary constants and substitute in the conditions to solve for these constants

which method is more widely used?

anonymous · Answer

also can i have a proof that the methods are equivalent?