Sail E0 Webinar

12th Grade > Mathematics

INVERSE TRIGONOMETRIC FUNCTIONS MCQs

Total Questions : 60 | Page 6 of 6 pages
Question 51. Complete solution set of tan2(sin1x)>1 is :
 
  1.    (−1−1√2)∪(1√2,1)
  2.    (−1√2,1√2)−{0}
  3.    (−1,1)−{0}
  4.    None of these
 Discuss Question
Answer: Option A. -> (−1−1√2)∪(1√2,1)
:
A
tan2(sin1x)>1
tan(sin1x)<1 or tan(sin1x)>1
π2<sin1x<π4 or π4<sin1x<π2
1<x<12 or 12<x<1
xϵ(112)(12,1)
Question 52. Find maximum value of x for which 2tan1x+cos1(1x21+x2) is independent of x.
  1.    0
  2.    2
  3.    3
  4.    1
 Discuss Question
Answer: Option A. -> 0
:
A
Let x=tanθ,π2<θ<π22θ+cos1cos2θ
(i)02θ<π2.2cos1cos2θ=2θ
So given expression =4θ=4tan1x
(ii)π2<θ0π<2θ0cos1cos2θ=2θ
So, given expression becomes independent of θ
For π2<θ0<x0
Question 53. If θ=tan1d1+a1a2+tan1d1+a2a3++tan1d1+an1an, where a1,a2,a3,an  are in A.P. with common difference d, then tanθ=
 
  1.    (n−1)d1+a1an
  2.    (n−1)da1+an
  3.    an−a1an+a1
  4.    nd1+a1an
 Discuss Question
Answer: Option A. -> (n−1)d1+a1an
:
A
θ=tan1a2a11+a1a2+tan1a3a21+a2a3++tan1anan11+an1an
=(tan1a2tan1a1)+(tan1a3tan1a2)++tan1anan11+an1an++(tan1antan1an1)
=tan1antan1a1
=tan1ana11+a1an=tan1(n1)d1+a1an
tanθ=(n1)d1+a1an
Question 54. The value of cos1(cos 5π3)+sin1(sin 5π3) is
  1.    0
  2.    π2
  3.    2π3
  4.    10π3
 Discuss Question
Answer: Option A. -> 0
:
A
cos1(cos5π3)+sin1(sin5π3)=cos1[cos(2ππ3)]+sin1[sin(2ππ3)]=π3π3=0.
Question 55. cot1[(cosα)12]tan1[(cosα)12]=x, then sinx=
  1.    tan2(α2)
  2.    cot2(α2)
  3.    tan α
  4.    cot(α2)
 Discuss Question
Answer: Option A. -> tan2(α2)
:
A
tan1[1cosα]tan1[cosα]=x
tan11cosαcosα1+cosαcosα=xtanx=1cosα2cosα
sinx=1cosα1+cosα=2sin2α22cos2α2=tan2(α2).
Question 56. cos[cos1(17)+sin1(17)]=
  1.    −13
  2.    0
  3.    13
  4.    49
 Discuss Question
Answer: Option B. -> 0
:
B
cos{cos1(17)+sin1(17)}=cosπ2=0
Question 57. The value of tan2(sec13)+cot2(cosec14) is
  1.    20
  2.    21
  3.    23
  4.    25
 Discuss Question
Answer: Option C. -> 23
:
C
Let Sec13=α,cosec14=βtan2α+cot2β=91+161=23
Question 58. If 2tan1x=sin12x1+x2, then:
  1.    x∈R
  2.    x≥1
  3.    x≤−1
  4.    −1≤x≤1
 Discuss Question
Answer: Option D. -> −1≤x≤1
:
D
Putting θ=tan1x,π2<θ<π2, we have
R.H.S. sin12tanθ1+tan2θ=sin1sin2θ=2θ=2tan1x
When π22θπ2 i.e., π4θπ4
i.e., 1x=tanθ1.
Question 59. If tan1(x)+tan1(y)+tan1(z)=π, then 1xy+1yz+1zx=
  1.    0
  2.    1
  3.    1xyz
  4.    xyz
 Discuss Question
Answer: Option B. -> 1
:
B
tan1(x)+tan1(y)+tan1(z)=π
tan1x+tan1y=πtan1z
x+y1xy=zx+y=z+xyz
x+y+z=xyz
Dividing by xyz, we get
1yz+1xz+1xy=1.
Note: Students should remember this question as a formula.
Question 60. The value of cos1(cos10)=
  1.    10
  2.    4π−10
  3.    2π+10
  4.    2π−10
 Discuss Question
Answer: Option B. -> 4π−10
:
B
cos1(cos10)=cos1(cos(4π10))=4π10

Latest Videos

Latest Test Papers