Mon June 11, 2012 By:

sir how ca i find sin10degree? Please give me the complete answer.

Expert Reply
Mon June 18, 2012
We know the value of sin(30) = 1/2
Now, sin 3x = 3 sinx - 4sin3x
For x = 10 degrees
so, sin 30 = 3 sin 10 - 4sin310
1/2 = 2* sin10 - 4sin310
Solving this considering it to be a third order polynomial, we get three roots out of the equation.
Imposing the condition that -1<sin x<1
The other two roots become inadmissible and we get the value of sin 10 = 0.1736
You can also use MacLaurin series for sin(x)
sin x = x ?x3/3! + x5/5! ?x7/7!+...
to get the approximate value of sin 10 degrees.
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