Asked by kim
If 'a' and 'b' are unit vectors that make an angle of 60 degrees with each other, calculate
l 3a - 5b l and l 8a + 3b l
the 'a' and 'b' have a carat of top of them
l 3a - 5b l and l 8a + 3b l
the 'a' and 'b' have a carat of top of them
Answers
Answered by
Steve
Let a=<1,0>
Then b=<1/2,√3/2>
Now you just add the components.
For example,
2a+3b = <2,0>+<3/2,3√3/2>
and |2a+3b|=√((2+3/2)^2+(0+3√3/2)^2) = √(49/4 + 27/4) = √76/2 = √19
Then b=<1/2,√3/2>
Now you just add the components.
For example,
2a+3b = <2,0>+<3/2,3√3/2>
and |2a+3b|=√((2+3/2)^2+(0+3√3/2)^2) = √(49/4 + 27/4) = √76/2 = √19