Well when she hits the water h=0 so
2t^2-t-6=0 factor
2t^2-4t+3t-6=0
2t(t-2)+3(t-2)=0
(2t+3)(t-2)=0, since t>0
t=2 seconds...
However it should be noted that h(t)=-2t^2+t+6 implies that
v(t)=dh/dt=-4t+1 and
a(t)=dv/dt=-4
Since this is a free fall equation, this would suggest that the acceleration due to gravity is -4, whether that is supposed to be -4ft/s^2 or -4m/s^2, it certainly is not on this planet! :D If it is -4ft/s^2 it could be on the Moon or if it is -4m/s^2 it could be on Mars.
Answer:
L.H.S.
= (cos5a.sin2a-cos4a.sin3a)/ (sin5a.sin2a-cos4a.cos3a)
Multiply numerator and denominator by 2.
= 2(cos5a.sin2a - cos4a.sin3a) / 2(sin5a.sin2a - cos4a.cos3a)
= (2cos5a.sin2a - 2cos4a.sin3a)/
(2sin5a.sin2a - 2cos4a.cos3a) = [sin(5a+2a)-sin(5a-2a)-sin(4a+3a)
+sin(4a-3a)]/[cos(5a-2a)-cos(5a+2a)-sin(4a-3a) +cos(4a+3a)]
= (sina - sin3a)/(cso3a-cosa)
= (-2cos2a.sina)/(-2sin2a.sina)
= cos2a/sin2a
= cot2a
= R.H.S.
The value is the tens place
