Answer:
Step-by-step explanation:
tanθ = 4/9
θ = arctan(4/9) ≈ 23.96°
Yes 90 is 1/10 of hundred
Question:
What is the common denominator of
in the complex fraction 
A) 
B) 
C) 
D) 
Answer:
Option D : 3 is the common denominator
Explanation:
It is given that the complex fraction 
We need to determine the common denominator of
from the complex fraction.
Let us consider the fraction 
To find the common denominator, let us take LCM.
Thus, rewriting the above fraction as,

The LCM can be determined by multiplying the denominators.
Thus, we get,

Thus, the common denominator is 3.
Hence, Option D is the correct answer.
Answer:
the required equation is; y = 21 sin(πt/6)
Step-by-step explanation:
Given the data in the question;
Water rises above sea level = 21 ft
Water drops below sea level = 21 ft
so
maximum = 21 ft and also
minimum = 21 ft
Amplitude = ( maximum + minimum ) / 2
Amplitude = ( 21 + 21 ) / 2
Amplitude = ( 21 + 21 ) / 2 = 42/2 = 21 ft
Period = 12 hours
and we know that; period = 2π/b
so
12 = 2π/b
12b = 2π
b = 2π / 12
b = π/6
Standard equation for simple harmonic is; y = asin(bt)
we substitute
y = 21 sin(πt/6)
Hence the required equation is; y = 21 sin(πt/6)