SOLUTION: Hi Totally Stuck Here i)If a and b are perpendicular, then by writing a= |a| and b= |b| simplify the expression (a-2b).(3a+5b) May just be how it is written but i cant get my

Question 366167: Hi Totally Stuck Here
i)If a and b are perpendicular, then by writing a= |a| and b= |b| simplify the expression (a-2b).(3a+5b)
May just be how it is written but i cant get my head around it
Many Thanks In Advance
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
The dot product is distributive.

Since the vectors are perpendicular,

Then,

.
.

So,

RELATED QUESTIONS
Evening All. Struggling on this vectors problem. i)If a and b are perpendicular, (answered by Edwin McCravy)

if a/b=4/3 then... (answered by Fombitz)

Simplify. Then evaluate the expression when a= 1 and b= 2... (answered by rapaljer)

if a= -2 and b= 3 what is... (answered by jim_thompson5910)

This problen says evaluate a+b/7 for a=67 and b=3 a+b/7=? and simplify the answer I am... (answered by Alan3354)

5{a-2b}-3a{4-b} (answered by rahman)

Simplify the expression... (answered by College Student)

if a=2 and b=3,then 3a-2b is equal... (answered by saifoo.khan)

simplify the expression 2ab^4-3a^2b^2-ab^4+a^2b^2 a. ab^4-2a^2b^2 b. 0 c.... (answered by ewatrrr)