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Question Number 193686 by Rupesh123 last updated on 18/Jun/23

Answered by mr W last updated on 18/Jun/23

Commented by mr W last updated on 18/Jun/23

c=(√(a^2 +b^2 ))  R=a+b  R^2 =b^2 +c^2 −2bc cos (α+θ)  a^2 +b^2 +2ab=b^2 +a^2 +b^2 −2b(√(a^2 +b^2 )) cos (α+θ)  b−2a=2(√(a^2 +b^2 )) cos (α+θ)  b−2a=2(√(a^2 +b^2 )) (cos α cos θ−sin α sin θ)  b−2a=2 (b cos θ−a sin θ)  a sin θ−((2a−b)/2)=b cos θ  a^2  sin^2  θ−(2a−b)a sin θ+(((2a−b)^2 )/4)=b^2 −b^2 sin^2  θ  (a^2 +b^2 ) sin^2  θ−(2a−b)a sin θ+((4a^2 −4ab−3b^2 )/4)=0  sin θ=(1/(2(a^2 +b^2 )))[a(2a−b)+(√(a^2 (2a−b)^2 −(a^2 +b^2 )(4a^2 −4ab−3b^2 )))]  Area=((c^2  sin θ)/2)=(1/4)[a(2a−b)+b(√(4a(2a−b)−b^2 ))]

c=a2+b2R=a+bR2=b2+c22bccos(α+θ)a2+b2+2ab=b2+a2+b22ba2+b2cos(α+θ)b2a=2a2+b2cos(α+θ)b2a=2a2+b2(cosαcosθsinαsinθ)b2a=2(bcosθasinθ)asinθ2ab2=bcosθa2sin2θ(2ab)asinθ+(2ab)24=b2b2sin2θ(a2+b2)sin2θ(2ab)asinθ+4a24ab3b24=0sinθ=12(a2+b2)[a(2ab)+a2(2ab)2(a2+b2)(4a24ab3b2)]Area=c2sinθ2=14[a(2ab)+b4a(2ab)b2]

Commented by Rupesh123 last updated on 18/Jun/23

[1] check last two lines (1/2 ? --> 1/4 ) [2] simplify last radical

Commented by Mingma last updated on 18/Jun/23

It's been a while sir! Neat work!

Commented by Rupesh123 last updated on 18/Jun/23

Perfect ��

Commented by ajfour last updated on 20/Jun/23

P(rcos φ, rsin φ)  r=a+b  r^2 cos^2 φ+(rsin φ−b)^2 =a^2 +b^2   ⇒  2ab+b^2 =2brsin φ  &  altitude of △ is ⊥ to base, so  ((rsin φ)/(rcos φ−a))=((a+rcos φ)/(2b−rsin φ))  ⇒  2brsin φ=r^2 −a^2   consider  (x/a)+(y/b)=1  or   bx+ay−ab=0  let   h=((∣brcos φ+arsin φ−ab∣)/( (√(a^2 +b^2 ))))  c=(√(a^2 +b^2 ))  rsin φ=a+(b/2)  h=((∣b(√((a+b)^2 −(a+(b/2))^2 ))+a^2 −((ab)/2)∣)/( (√(a^2 +b^2 ))))  △=((ch)/2)  =(b^2 /2)∣(√((3/4)+(a/b)))+(a^2 /b^2 )−(a/(2b))∣

P(rcosϕ,rsinϕ)r=a+br2cos2ϕ+(rsinϕb)2=a2+b22ab+b2=2brsinϕ&altitudeofistobase,sorsinϕrcosϕa=a+rcosϕ2brsinϕ2brsinϕ=r2a2considerxa+yb=1orbx+ayab=0leth=brcosϕ+arsinϕaba2+b2c=a2+b2rsinϕ=a+b2h=b(a+b)2(a+b2)2+a2ab2a2+b2=ch2=b2234+ab+a2b2a2b

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