/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 77 Prove that, for vectors r, s, u,... [FREE SOLUTION] | 91影视

91影视

Prove that, for vectors r, s, u, and v in 3,role="math" localid="1650038347684" (rs)(uv)=(ru)(sv)(rv)(su)

Short Answer

Expert verified

Hence, we prove that(rs)(uv)=(ru)(sv)(rv)(su).

Step by step solution

01

Step 1. Given Information

Prove that, for vectors r, s, u, and v in 3,(rs)(uv)=(ru)(sv)(rv)(su)

02

Step 2. Let r=(r1,r2,r3), s=(s1,s2,s3), u=(u1,u2,u3) and v=(v1,v2,v3)

Firstly finding the value of rs.

role="math" localid="1650036273470" rs=ijkr1r2r3s1s2s3rs=ir2r3s2s3-jr1r3s1s3+kr1r2s1s2rs=i(r2s3-r3s2)-j(r1s3-r3s1)+k(r1s2-r2s1)rs=r2s3-r3s2,r1s3-r3s1,r1s2-r2s1

03

Step 3. Now finding the value of u×v

uv=ijku1u2u3v1v2v3uv=iu2u3v2v3-ju1u3v1v3+ku1u2v1v2uv=i(u2v3-u3v2)-j(u1v3-u3v1)+k(u1v2-u2v1)uv=u2v3-u3v2,u1v3-u3v1,u1v2-u2v1

04

Step 4. Now finding the value of (r×s)·(u×v)

(rs)(uv)=r2s3-r3s2,r1s3-r3s1,r1s2-r2s1u2v3-u3v2,u1v3-u3v1,u1v2-u2v1(rs)(uv)=r2s3-r3s2(u2v3-u3v2)+(r1s3-r3s1)(u1v3-u3v1)+(r1s2-r2s1)(u1v2-u2v1)(rs)(uv)=r2s3(u2v3-u3v2)-r3s2(u2v3-u3v2)+r1s3(u1v3-u3v1)-r3s1(u1v3-u3v1)+r1s2(u1v2-u2v1)-r2s1(u1v2-u2v1)(rs)(uv)=r2s3u2v3-r2s3u3v2-r3s2u2v3+r3s2u3v2+r1s3u1v3-r1s3u3v1-r3s1u1v3+r3s1u3v1+r1s2u1v2-r1s2u2v1-r2s1u1v2+r2s1u2v1(rs)(uv)=(r2s3u2v3+r3s2u3v2+r1s3u1v3+r3s1u3v1+r1s2u1v2+r2s1u2v1)-(r2s3u3v2+r3s2u2v3+r1s3u3v1+r3s1u1v3+r1s2u2v1+r2s1u1v2)

05

Step 5. Now finding the value of r·u

ru=(r1,r2,r3)(u1,u2,u3)ru=(r1u1+r2u2+r3u3)

Now finding the value ofsv

role="math" localid="1650037294978" sv=(s1,s2,s3)(v1,v2,v3)sv=(s1v1+s2v2+s3v3)

Now finding the value of (ru)(sv)

role="math" localid="1650038075755" (ru)(sv)=(r1u1+r2u2+r3u3)(s1v1+s2v2+s3v3)(ru)(sv)=r1u1(s1v1+s2v2+s3v3)+r2u2(s1v1+s2v2+s3v3)+r3u3(s1v1+s2v2+s3v3)(ru)(sv)=r1u1s1v1+r1u1s2v2+r1u1s3v3+r2u2s1v1+r2u2s2v2+r2u2s3v3+r3u3s1v1+r3u3s2v2+r3u3s3v3

06

Step 5. Now finding the value of r·v

rv=(r1,r2,r3)(v1,v2,v3)rv=(r1v1+r2v2+r3v3)

Now finding the value ofsu

su=(s1,s2,s3)(u1,u2,u3)su=(s1u1+s2u2+s3u3)

Now finding the value of(rv)(su)

role="math" localid="1650038126363" (rv)(su)=(r1v1+r2v2+r3v3)(s1u1+s2u2+s3u3)(rv)(su)=r1v1(s1u1+s2u2+s3u3)+r2v2(s1u1+s2u2+s3u3)+r3v3(s1u1+s2u2+s3u3)(rv)(su)=r1v1s1u1+r1v1s2u2+r1v1s3u3+r2v2s1u1+r2v2s2u2+r2v2s3u3+r3v3s1u1+r3v3s2u2+r3v3s3u3

07

Step 7. Now finding the value of (r·u)(s·v)−(r·v)(s·u)

(ru)(sv)(rv)(su)=r1u1s1v1+r1u1s2v2+r1u1s3v3+r2u2s1v1+r2u2s2v2+r2u2s3v3+r3u3s1v1+r3u3s2v2+r3u3s3v3-(r1v1s1u1+r1v1s2u2+r1v1s3u3+r2v2s1u1+r2v2s2u2+r2v2s3u3+r3v3s1u1+r3v3s2u2+r3v3s3u3)(ru)(sv)(rv)(su)=r1u1s1v1+r1u1s2v2+r1u1s3v3+r2u2s1v1+r2u2s2v2+r2u2s3v3+r3u3s1v1+r3u3s2v2+r3u3s3v3-r1v1s1u1-r1v1s2u2-r1v1s3u3-r2v2s1u1-r2v2s2u2-r2v2s3u3-r3v3s1u1-r3v3s2u2-r3v3s3u3(ru)(sv)(rv)(su)=(r2s3u2v3+r3s2u3v2+r1s3u1v3+r3s1u3v1+r1s2u1v2+r2s1u2v1)-(r2s3u3v2+r3s2u2v3+r1s3u3v1+r3s1u1v3+r1s2u2v1+r2s1u1v2)

Hence, prove that(rs)(uv)=(ru)(sv)(rv)(su)

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Study anywhere. Anytime. Across all devices.