How do you evaluate 2 sin (pi/6) - 3 tan (pi/6)?

1 Answer
Apr 3, 2016

1 - sqrt3 ≈ -0.732

Explanation:

Using the color(blue)" exact value triangle "

For angles pi/3 , pi/6 , pi/2

with sides of length 1 ,sqrt3" and hypotenuse " 2

From this : sin(pi/6) = 1/2" and " tan(pi/6) = 1/sqrt3

hence 2sin(pi/6) = 2xx1/2 = 1

and 3tan(pi/6) = 3xx1/sqrt3

rationalising the denominator

3xx1/sqrt3 = 3xxsqrt3/(sqrt3xxsqrt3) = (3sqrt3)/3 = sqrt3

rArr2sin(pi/6) - 3tan(pi/6) = 1 - sqrt3 ≈ -0.732