Home
Class 11
MATHS
If veca and vecb are two vectors, such t...

If `veca and vecb` are two vectors, such that `veca.vecblt0 and |veca.vecb|=|vecaxxvecb|` then the angle between angles between the vectors `veca and vecb` is

A

`pi`

B

`7pi//4`

C

`pi//4`

D

`3pi//4`

Text Solution

Verified by Experts

The correct Answer is:
d
`|veca.vecb|=|vecaxxvecb|`
`Rightarrow|veca||vecb||costheta|=|veca||vecb||sin theta|`
(where,`theta` is the angle between `veca and vecb`)
`Rightarrow |costheta|= |sintheta|`
`Rightarrow theta= pi/4 or (3pi)/4(as 0 le thetalepi)`
But `veca.vecb lt 0`, therefore, `theta= (3pi)/4`
Promotional Banner

Topper's Solved these Questions

  • DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS

    CENGAGE|Exercise Exercise 2.1|18 Videos

  • DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS

    CENGAGE|Exercise Exercise 2.2|15 Videos

  • CONIC SECTIONS

    CENGAGE|Exercise Solved Examples And Exercises|1255 Videos

  • LIMITS AND DERIVATIVES

    CENGAGE|Exercise Solved Examples And Exercises|288 Videos

Similar Questions

Explore conceptually related problems

If veca and vecb are non - zero vectors such that |veca + vecb| = |veca - 2vecb| then

veca and vecb are two vectors such that |veca|=1 ,|vecb|=4 and veca. Vecb =2 . If vecc = (2vecaxx vecb) - 3vecb then find angle between vecb and vecc .

If veca and vecb are two vectors such that |veca|=10,|vecb|=15" ""and"" "veca.vecb=75sqrt(2), find the angle between veca and vecb .

If veca and vecb are unit vectors such that (veca +vecb). (2veca + 3vecb)xx(3veca - 2vecb)=vec0 then angle between veca and vecb is

If veca,vecb,vecc are three vectors such that veca+2vecb+vecc=vec0 and |veca|=3,|vecb|=4,|vecc|=7 , find the angle between veca and vecb .