(1+R) to the power of n = A/P
(1+R) to the power of 4 = 3238.17/2600
(1+R) to the power of 4 = 1.245
(1+R) = 4 root 1.245
1+r = 1.05631
R = 0.05631
The interest rate percentage is 5.63% (2dp)
Lets solve for t in the height equation:
h = 7 cos (pi/3 t)
cos (pi/3 t) = h/7
pi/3 t = cos^-1 (h/7)
t = (3/pi) <span>cos^-1 (h/7)
then we substitute:
</span>t = (3/pi) <span>cos^-1 (1/7)
</span>t = 78.1 s
t = (3/pi) <span>cos^-1 (3/7)
</span>t= 61.71
t = (3/pi) <span>cos^-1 (5/7)
</span>t = 42.41
those are the times in seconds respectively.
It's either choice B. or D. I'm so sorry i cant remember completely.
Y=3*x+38,
where 38 is our start value, that is y(0)=38, and x is the number of hours.