© examsiri.com
Question : 93 of 180
Marks:
+1,
-0
Solution:
Two vectors
and
are orthogonal to each other, if their scalar product is zero
i.e.
.=0 Here,
=cos‌ωt‌+sin‌ωt‌ and
=cos‌‌+sin‌‌∴
.=(cos‌ωt‌+sin‌ωt) (cos‌‌+sin‌‌)=
cos‌ωt‌cos‌+sin‌ωt‌sin‌(∵.=.=1 and
.=.=0)=
cos(ωt−)(∵cos(A−B)=cos‌A‌cos+sin‌A‌sin‌B)But
.=0 (as
and
orthogonal to each other)
∴
cos(ωt−)=0cos(ωt−)=cos‌ or
ωt−== or
© examsiri.com
Go to Question: