Question #4931b

1 Answer
Apr 17, 2017

x= 2/9 ysqrt(36-y^2)

Explanation:

The secret lies in using trig identities: sin(2t) = 2sin(t)cost(t); sin(t) = sqrt(1-cos^2(t)).
We can write cos(t) = y/6; and x = 4*2sin(t)cos(t) .
That is, x = 8cos(t)sqrt(1-cos^2(t)); than replace cos(t), so x = 8*y/6sqrt(1-(y/6)^2) =8/36ysqrt(36-y^2) = 2/9ysqrt(36-y^2).