In the Qiskit textbook, I'm stuck on one of the exercises in section 2.2. The question is:
The answer has already been covered in this question here, and is defined as:
This makes sense to me - we're basically factoring out the first qubit. However, for my own benefit, I tried multiplying out the vectors and I get different results:
Using the original form:
Using the answer supplied:
Why don't these give the same values?
n.b. Apologies for the use of images - I only had MS Word at my disposal and couldn't find an easy way to export the equations bar screen-shotting.