1800-150-456-789
FlagBACK
Flag Trigonometry> how to calculate tan 15 degree value
question mark

how to calculate tan 15 degree value

geeta , 10 Years ago
Grade 11
anser 2 Answers
Rinkoo Gupta

Last Activity: 10 Years ago

tan15=tan(45-30)
=(tan45-tan30)/1+tan45tan30
=(1-1/sqrt3)/1+1/sqrt3
=sqrt3-1)/sqrt3+1
=(sqrt3-1)(sqrt3-1)/2
=(4-2sqrt3)/2
=2-sqrt3
Thanks & Regards
Rinkoo Gupta
AskIITians Faculty

Jitender Singh

Last Activity: 10 Years ago

Ans:
tan2\theta = \frac{2tan\theta }{1-tan^{2}\theta }
tan30 = \frac{2tan15 }{1-tan^{2}15 }
\frac{2tan15 }{1-tan^{2}15 } = \frac{1}{\sqrt{3}}
tan^{2}15+2\sqrt{3}tan15-1=0
tan15 = \frac{-2\sqrt{3}\pm \sqrt{12+4}}{2} = \frac{-2\sqrt{3}\pm 4}{2}
tan15 = \frac{4-2\sqrt{3}}{2} = 2-\sqrt{3}
Thanks & Regards
Jitender Singh
IIT Delhi
askIITians Faculty

Provide a better Answer & Earn Cool Goodies

Enter text here...
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


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...

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: 2 Year ago(s)

question mark
\tFind the general solution of equation tan3∂=cot2∂For all angles between -720 and +720
Trigonometry
0 Answer Available

Last Activity: 2 Year ago(s)

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

Last Activity: 2 Year ago(s)

question mark
cos^2 13ºcos^2 47º+cos^2 73º =? …..................
Trigonometry
0 Answer Available

Last Activity: 2 Year ago(s)

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
0 Answer Available

Last Activity: 2 Year ago(s)