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- General equation for the magnitude of the difference vector of two parallel or antiparallel vectors

Hi everyone,

While finding the solution for one of my exercises, I found the following answer. I'm seriously questioning if the equations provided in that answer are reversed. According to my understanding, if two vectors ##\vec{S}## and ##\vec{T}## are parallel (same direction) the magnitude of the difference vector ##\vec{S}-\vec{T}## is:

$$

||\vec{S}| - |\vec{T}||

$$

If the vectors are antiparallel, the magnitude of the difference vector is:

$$

|\vec{S}| + |\vec{T}|

$$

Did the author of that answer wrote the equations in the wrong places or am I missing something?

Thanks.

While finding the solution for one of my exercises, I found the following answer. I'm seriously questioning if the equations provided in that answer are reversed. According to my understanding, if two vectors ##\vec{S}## and ##\vec{T}## are parallel (same direction) the magnitude of the difference vector ##\vec{S}-\vec{T}## is:

$$

||\vec{S}| - |\vec{T}||

$$

If the vectors are antiparallel, the magnitude of the difference vector is:

$$

|\vec{S}| + |\vec{T}|

$$

Did the author of that answer wrote the equations in the wrong places or am I missing something?

Thanks.