Your notation leaves much to be desired.find |2a+b|^2, if |vector b|=5, |vector a|=4 |2a-b|=7 , been stuck for hour.
So, the a and b is vector coordinates, and |a| is lenght of vector, same as |2a-b|. I'm sorry that's all i can give you, that's how the task was given to me.Your notation leaves much to be desired.
Are we to assume that the following is correct?
[imath]{\left\| {\overrightarrow a + \overrightarrow b } \right\|^2} = \left( {\overrightarrow a + \overrightarrow b } \right) \cdot \left( {\overrightarrow a + \overrightarrow b } \right)[/imath]
Hint: [imath]\mid 2 \textbf{a} - \textbf{b} \mid ^2 = (2 \textbf{a} - \textbf{b} ) \cdot (2 \textbf{a} - \textbf{b} ) = 4 a^2 + b^2 - 4 \textbf{a} \cdot \textbf{b}[/imath].find |2a+b|^2, if |vector b|=5, |vector a|=4 |2a-b|=7 , been stuck for hour.
If we use [imath]{\left\| {\overrightarrow a } \right\|^2} = \overrightarrow a ~\overrightarrow { \cdot a} [/imath]So, the a and b is vector coordinates, and |a| is lenght of vector, same as |2a-b|. I'm sorry that's all i can give you, that's how the task was given to me.
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