Home
Class 12
MATHS
sin^(10)x+cos^(10)x=29/16cos^4 2x...

`sin^(10)x+cos^(10)x=29/16cos^4 2x`

Text Solution

Verified by Experts

`sin^(10) x+cos^(10)x=29/16 cos^(4) 2x`
`rArr ((1- cos 2x)/2)^(5) + ((1+cos 2x)/2)^(5) =29/16 cos^(4) 2x`
Let `cos 2x=t`. Then
`((1-t)/2)^(5)+((1+t)/2)^(5) =29/16 t^(4)`
or `24 t^(4)-10 t^(2) -1=0`
or `(2t^(2) -1) (12 t^(2) +1) =0`
or `t^(2) =1/2`
or `cos^(2) 2x=1/2 =(1/sqrt(2))^(2)=("cos" pi/4)^(2)`
or `2x=n pi pm pi/4, n in Z`
or `x= (n pi)/2 pm pi/8, n in Z`
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRIC EQUATIONS

    CENGAGE|Exercise Exercise 4.1|12 Videos
  • TRIGONOMETRIC EQUATIONS

    CENGAGE|Exercise Exercise 4.2|6 Videos
  • TRIGNOMETRIC RATIOS IDENTITIES AND TRIGNOMETRIC EQUATIONS

    CENGAGE|Exercise Question Bank|34 Videos
  • TRIGONOMETRIC FUNCTIONS

    CENGAGE|Exercise SINGLE CORRECT ANSWER TYPE|38 Videos

Similar Questions

Explore conceptually related problems

Number of solutions of equation 16(sin^10x+cos^10x)=29 cos^4 2x in interval [-pi,pi] is

sin ^ (10) x + cos ^ (10) x = (29) / (16) cos ^ (4) 2x

If sin^(4)2x+cos^(4)2x=sin2x*cos2x then x=

If sin x + sin ^(2) x=1, then the value of cos ^(12) x+3 cos ^(10) x+3 cos ^(8) x + cos ^(6) x-2 is equal to

sin ^ (2) x, cos x ^ (2) x, 1cos ^ (2) x, sin ^ (2) x, 1-10,12,2] | = 0

|(sin^(2) x,cos^(2) x,1),(cos^(2) x,sin^(2) x,1),(- 10,12,2)| =