Home
Class 12
MATHS
Let A B C be a triangle such that /A C B...

Let `A B C` be a triangle such that `/_A C B=pi/6` and let `a , ba n dc` denote the lengths of the side opposite to `A , B ,a n dC` respectively. The value(s) of `x` for which `a=x^2+x+1,b=x^2-1,a n dc=2x+1` is(are) `-(2+sqrt(3))` (b) `1+sqrt(3)` `2+sqrt(3)` (d) `4sqrt(3)`

A

`-(2 + sqrt3)`

B

`1+ sqrt3`

C

`2+sqrt3`

D

`4 sqrt3`

Text Solution

Verified by Experts

The correct Answer is:
B
Using cosine rule for `angleC`, we get
`(sqrt3)/(2) = ((x^(2) + x+1)^(2) + (x^(2) -1)^(2) - (2x + 1)^(2))/(2 (x^(2) + x + 1) (x^(2) -1))`
or `sqrt3 = (2x^(2) + 2x -1)/(x^(2) + x + 1)`
or `(sqrt3 -2) x^(2) + (sqrt3 -2) x + (sqrt3 +1) = 0`
or `x = ((2 -sqrt3) +- sqrt3)/(2(sqrt3 -2))`
or `x = -(2 + sqrt3), 1 + sqrt3`
or `x = 1 + sqrt3 " as " (x gt 0)`
Promotional Banner

Topper's Solved these Questions

  • PROPERTIES AND SOLUTIONS OF TRIANGLE

    CENGAGE|Exercise JEE Main Previous Year|2 Videos

  • PROGRESSION AND SERIES

    CENGAGE|Exercise ARCHIVES (MATRIX MATCH TYPE )|1 Videos

  • PROPERTIES OF TRIANGLE, HEIGHT AND DISTANCE

    CENGAGE|Exercise Question Bank|15 Videos

Similar Questions

Explore conceptually related problems

If the angle A ,Ba n dC of a triangle are in an arithmetic propression and if a , ba n dc denote the lengths of the sides opposite to A ,Ba n dC respectively, then the value of the expression a/csin2C+c/asin2A is 1/2 (b) (sqrt(3))/2 (c) 1 (d) sqrt(3)

Consider a triangle A B C and let a , ba n dc denote the lengths of the sides opposite to vertices A , B ,a n dC , respectively. Suppose a=6,b=10 , and the area of triangle is 15sqrt(3)dot If /_A C B is obtuse and if r denotes the radius of the incircle of the triangle, then the value of r^2 is

If tan^(-1)x+2cot^(-1)x=(2pi)/3, then x , is equal to (a) (sqrt(3)-1)/(sqrt(3)+1) (b) 3 (c) sqrt(3) (d) sqrt(2)

The length of the chord of the parabola y^2=x which is bisected at the point (2, 1) is (a) 2sqrt(3) (b) 4sqrt(3) (c) 3sqrt(2) (d) 2sqrt(5)

If x=1+1/(3+1/(2+1/(3+1/(2oo)))) a sqrt(5/2) b. sqrt(3/2) c. sqrt(7/3) d. sqrt(5/3)

Vertices of a variable acute angled triangle A B C lies on a fixed circle. Also, a ,b ,ca n dA ,B ,C are lengths of sides and angles of triangle A B C , respectively. If x_1, x_2a n dx_3 are distances of orthocenter from A ,Ba n dC , respectively, then the maximum value of ((dx_1)/(d a)+(dx_2)/(d b)+(dx_3)/(d c)) is -sqrt(3) b. -3sqrt(3) c. sqrt(3) d. 3sqrt(3)

int_(-1)^(1/2)(e^x(2-x^2)dx)/((1-x)sqrt(1-x^2))i se q u a lto (sqrt(e))/2(sqrt(3)+1) (b) (sqrt(3e))/2 sqrt(3e) (d) sqrt(e/3)

If n-1C_r=(k^2-3)^nC_(r+1), then (a) (-oo,-2] (b) [2,oo) (c) [-sqrt3, sqrt3] (d) (sqrt3,2]

If cos^-1((x^2 -1)/(x^2+1))+ tan^-1 ((2x)/(x^2-1)) = (2pi)/3 , then x equal to (A) sqrt(3) (B) 2+sqrt(3) (C) 2-sqrt(3) (D) -sqrt(3)

The function f(x)=x(x+4)e^(-x//2) has its local maxima at x=adot Then (a) a=2sqrt(2) (b) a=1-sqrt(3) (c) a=-1+sqrt(3) (d) a=-4