Open study

is now brainly

With Brainly you can:

  • Get homework help from millions of students and moderators
  • Learn how to solve problems with step-by-step explanations
  • Share your knowledge and earn points by helping other students
  • Learn anywhere, anytime with the Brainly app!

A community for students.

Help please :) Yr11 3 unit question on trig In triangle ABC, acosA = bcosB. Prove using the cosine rule, that the triangle is either isosceles or right-angled

Mathematics
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your free account and access expert answers to this and thousands of other questions

Do u knw cos rule?
yep...
good:) so vat is cosA?

Not the answer you are looking for?

Search for more explanations.

Ask your own question

Other answers:

b^2 + c^2 - a^2 / 2bc
cosB=?
a^2 +c^2 - b^2 / 2ac
good:)
Nw if u r to prove that the triangle is isoscles u need to show that a=b or b=c or a=c. if u r to show it is a right angled triangle u should show pythagoras theorem is valid. \[a\cos A=b\cos B\] \[a* \frac{ b^2+c^2-a^2 }{ 2bc}=b*\frac{ a^2+c^2-b^2 }{ 2ac }\] vat do u get when u simplify this? @AonZ
2c^3 a^2 - 2a^4 c - 2c^3 b^2 + 2b^4 c = 0
u can factor out 2c.
2c ( b^4 - c^2 b^2 + a^2 c^2 - a^4) = 0 this right so far?
yup:) good:) nw divide by 2c both sides.
ok done that. btw im writing it down
ok:)
u will get this. b^4 - c^2 b^2 + a^2 c^2 - a^4=0 try to factorise this.
(b^2 - a^2)(b^2 +a^2 -c^2)
(b+a)(b-a)(b^2+a^2 - c^2)
(b+a)(b-a)(b^2+a^2 - c^2)=0 Divide by (b+a)(b-a) both sides. vat do u get?
b^2 +a^2 - c^2 = 0
you can tell its right angle by looking at this.. but how do you tell if its isosceles?
u r nt asked to prove both right? either one of that?
oh i guess :)
i still think it means to prove that the triangle must be right or isoscles but it cant be scalene
but can we show it isoscles anyways?
let me think. hav to go nw. will be back in 15 mnts
(b+a)(b-a)(b^2+a^2 - c^2) =0 gives (b+a)=0 OR (b-a)= 0 OR (b^2+a^2 - c^2)=0 so, b-a = 0 --->a=b----->isosceles (b^2+a^2 - c^2)=0 --->right as you already know.
ohh xDDDD THANKS!! Shame i can only give medal to 1 person :(
hey, i am not here for medals ;)
Welcome:) you can give it to @gohangoku58
cos he/she deserves it most:)
:O You made him solve the whole thing and i deserve it!??
lol
yup:) it was u who pointed out the isoscles one:)

Not the answer you are looking for?

Search for more explanations.

Ask your own question