+91-735-322-1155
FlagBACK
Flag Trigonometry> 2 sin^4(pi/8)+2 sin^4(3pi/8)=3/2 how?...
question mark

2 sin^4(pi/8)+2 sin^4(3pi/8)=3/2 how?

sarthak , 11 Years ago
Grade 11
anser 1 Answers
Y RAJYALAKSHMI
2sin4(pi/8) + sin4(3pi/8) = 2sin4(pi/8) + 2sin4((pi/2) – pi/8))
= 2sin4(pi/8) + 2cos4(pi/8) = 2( sin4(pi/8) + cos4(pi/8))   (add & subtract 2sin2(pi/8)cos2(pi/8))
= 2[(sin2(pi/8) + cos2(pi/8))2 – 2sin2(pi/8)cos2(pi/8))]
= 2[1 – 2sin2(pi/8)cos2(pi/8)] = 2 – 4 sin2(pi/8) cos2(pi/8) = 2 – sin2(pi/4)
= 2 – ½ = 3/2
 
ApprovedApproved
Last Activity: 11 Years ago
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Other Related Questions on trigonometry

question mark
In ABC, if cot A+cot B+cot C = cosecA cosecB cosecC, then prove that ABC is right angle triangle.
trigonometry
1 Answer Available

Last Activity: 3 Years ago

question mark
  • Find the general solution of equation tan3∂=cot2∂
For all angles between -720 and +720
trigonometry
1 Answer Available

Last Activity: 3 Years ago

question mark
To prove : Cosec(45 degree - A)Cosec(45 degree + A) = 2SecA
trigonometry
1 Answer Available

Last Activity: 3 Years ago

question mark
Derive a formula for the area of the triangle, given b, A, B, and C. That is, derive the formula: (b^2sinAsinC)/(2sinB)
trigonometry
1 Answer Available

Last Activity: 3 Years ago

question mark
WHAT IS THE LIMIT WHEN X TOWARDS TO 0 OF sin6x/5x ? lim𝑥→0 𝑠𝑖𝑛6𝑥/5𝑥 
trigonometry
1 Answer Available

Last Activity: 3 Years ago