Question

Sollutions of triangles

Answer 1

If in a triangle ABC,
\[\huge (a+b+c)(b+c-a)= k.bc\] then
\[\huge k \in ?\]

(A) k<0
(B)k>6
(C)0<k<4
(D)k>4

Answer 2

@ganeshie8 @sidsiddhartha

Answer 3

i really need some brush up lol :P

Answer 4

ok lemme try :)

Answer 5

I got the solution in a book
http://books.google.co.in/books?id=RTb9Cm9N3rgC&pg=SL13-PA106&lpg=SL13-PA106&dq=If+in+a+triangle+ABC,+(a%2Bb%2Bc)(b%2Bc-a)+%3Dkbc+then&source=bl&ots=In8VQKV40c&sig=xfuv9C5OsBJtssNz3jN3zbqiqsA&hl=en&sa=X&ei=6NdpVJ4tzrW4BKLpgNgE&ved=0CCkQ6AEwAw#v=onepage&q=If%20in%20a%20triangle%20ABC%2C%20(a%2Bb%2Bc)(b%2Bc-a)%20%3Dkbc%20then&f=false

Answer 6

\[(a+b+c)(b+c-a)=kbc\\2s(2s-2a)=kbc\\ \frac{ s(s-a) }{ bc }=\frac{ k }{ 4 }\]

Answer 7

so \[\cos^2(A/2)=k/4\]

Answer 8

yup

Answer 9

now\[0<\cos^2(A/2)<1\]

Answer 10

0<k<4
cool !

Answer 11

\[0<k/4<1\\0<k<4\]
so i'm getting C

Answer 12

yesh :)

Answer 13

yes , I don't have the options but c shou;ld be correct

Answer 14

phir se ye sab kuch padna parega kuch yaad nahi :(

Answer 15

how much time does one lecture last at IIT
haha tumne to padh liya tha ab mera wqt hai

Answer 16

45 min to 1 hour approx , lekin class meon sunta kaun hai

Answer 17

*mein

Answer 18

LOL

Answer 19

pakta hai kya haha

Answer 20

alltime :P

Answer 21

hahaha