Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 120 off


In a triangle ABC, 2ac sin 1/2 (A – B + C) =
(A) a2+b2-c2                                              (B) c2+a2-b2
(C) b2-c2-a2                                               (D) c2-a2-b2

7 years ago


Answers : (1)



so A+C = Pi - B

so here it will be :  2ac.sin(Pi/2 -B) = 2ac.cosB

by cosine rule, we have: c2+a2-b2 = 2ac cos B

option B


Please feel free to post as many doubts on our disucssion forum as you can. If you find any question difficult
to understand - post it here and we will get you the answer and detailed solution very quickly.We are all
IITians and here to help you in your IIT JEE preparation. All the best.

IIT Kgp - 05 batch

7 years ago

Post Your Answer

Other Related Questions on Trigonometry

If sinx = cos2x, then cos2x(1 + cos2x) is equal to (A) 0 (B) 1 (C) 2 (D) none of these
Anoushka Arora, Answer is (B) 1 Explanation Squaring on both sides, we get sin 2 x= cos 4 x 1-cos 2 x=cos 4 x So cos 2 x+cos 4 x = 1 cos 2 x(1+cos 2 x) = 1 Hence Proved. Warm Regards,...
Karthikk Kumaresan 13 days ago
proove that {cot^a(secA-1)}/1+sinA = sec^2A pls help me solve this problem and thak you
I hope you want to prove follwing identity. If yes then this not correct question as this can be never be true . For example put A = 45, LHS and RHS are not equal.
Ajay 3 months ago
Hi Gaurang the question still does not seem to be correct. Can you post the screenshot of question attachment
Ajay 3 months ago
Yes ajay sir I didnt type it correct so it was amistke please help in soving this one and thankyou very much
Gaurang Kotasthane 3 months ago
if x 1 , x 2 , x 3 , x 4 are the roots of the equation x 4 -x 3 sin 2 beta + x 2 cos 2 beta – x cos beta – sin beta = 0 then ∑ i=1 to 4 tan -1 x i is ?
Sum of roots taken 3 at a ime means abc + bcd + acd + abd ie all possible combinations of 3 roots out of 4.Sum of roots = sin 2ßSum of roots taken 2 at a time = cos 2ßSum of roots taken 3 at...
Faiz 2 days ago
Let the roots be a,b,c,d...Then tan-¹ a + tan-¹ b + tan-¹ + tan-¹ d is equal to...tan-¹ [ (sum of roots - sum of roots taken 3 at a time) / (1 - sum of roots taken 2 at a time + product of...
Faiz 2 days ago
A line is such that its segment between the straight lines 5x-y-4=0 and 3x-4y-4=0 is bisected at the point (1,5).obtain the equation
assume the eqn. of line be y = mx + c it has two constants m and c . after passing the points from (1,5) the eqn. becomes, 5 = m + c ….........................................(1) let this...
Vikas TU 2 months ago
If we consider n×0=0 where n is any number not equals to 0 Let n= 2. 2×0=0 2=0÷0. =? So if any numbér is divided its self it should be 1 so what about 0÷0=? If 0÷0is infinite Then 2 =...
Its answer lies in you u are confused that what is the value of 0÷0. Its value is not defined or non existent so nothing can be said about 0÷0. Also any number divided by...
Gundeep Singh one month ago
modulus operator is a bit tough for me and i cant understand a thing in some questions for eg lim x->0- mod(x)/x=-1; how does this work mod must always be positive right?
Posting again as the there is bug in website which does not properly dispay inequalities. Its not difficult if you visualise it graphically. Search google for desmos graphing calculator and ...
Ajay 2 months ago
Its not difficult if you visualise it graphically. Search google for desmos graphing calculator and plot the graph for this function y= mod(x)/x. You will see why left hand limit for thins...
Ajay 2 months ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,000 off

Get extra R 120 off

More Questions On Trigonometry

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details