Given that tanx = 1/sqr(15) and secx -4/sqr(15)
find the value of sinx
Since the tangent is positive and the secant (or cosine) is negative, x must lie in quadrant III
construct a triangle showing an opposite side of 1 and an adjacent side of √15
by Pythagoras, the hypotenuse is 4.
so in III
sinx = -1/4