- #1
danago
Gold Member
- 1,123
- 4
[tex]\overrightarrow r (t)[/tex] is a vector valued function given by:
[tex]
\overrightarrow r (t) = x(t)\overrightarrow i + y(t)\overrightarrow j
[/tex]
if [tex]h(t) = \left| {\overrightarrow r (t)} \right|[/tex], show that the following is true:
[tex]
\overrightarrow r (t) \bullet \overrightarrow r '(t) = x(t)\overrightarrow i + y(t)\overrightarrow j
[/tex]
Now, my first question is: how can a dot product of two vectors possibly be another vector? Isnt the dot product always a scalar quanitity? Am i correct in saying this, and is there a typo in the question, or am i completely missing something?
Thanks in advance,
Dan.
[tex]
\overrightarrow r (t) = x(t)\overrightarrow i + y(t)\overrightarrow j
[/tex]
if [tex]h(t) = \left| {\overrightarrow r (t)} \right|[/tex], show that the following is true:
[tex]
\overrightarrow r (t) \bullet \overrightarrow r '(t) = x(t)\overrightarrow i + y(t)\overrightarrow j
[/tex]
Now, my first question is: how can a dot product of two vectors possibly be another vector? Isnt the dot product always a scalar quanitity? Am i correct in saying this, and is there a typo in the question, or am i completely missing something?
Thanks in advance,
Dan.