Edit MetaData
6 years ago
5 years, 2 months ago
Given: sin8θ+cos8θ=1
Dividing by 2–√on both sides,12√sin8θ+12√cos8θ=12√—(1)
Since, sin45=cos45=12√
LHSof (1)=>cos45sin8θ+sin45cos8θ—(2)
RHSof (1)=12√=sin45
Since sin(A+B)=sinAcosB+cosAsinB,
(2)=>sin(45+8θ)=12√=sin45=sin135
Considering RHS=sin45
=>45+8θ=45=>8θ=0=>θ=0, but θ is not 0 (given)
Considering RHS=sin135
=>45+8θ=135=>8θ=90=>θ=908=454—(3)
Requested answer is cos2θ∗sin2θ=(cosθ∗sinθ)2=([2∗cosθ∗sinθ]2)2—(4)
Since 2sinθcosθ=sin2θ,(4) can be written as (sin2θ)24=(sin(2∗454))24
=(sin45/2)^2/4------->(5)
sin(45/2)=0.3827,(5) can be evaluated to 0.036612
Quick, Easy and Effective Revision
By proceeding you agree to create your account
Free CAT Formulae PDF will be sent to your email address soon !!!