First you need to find how much 20% of $18.50 is. To do this, you need to multiply 18.50 by 20% which in decimal form is 0.2
$18.50x0.2=$3.70
Now you need to subtract $3.70 from $18.50
$18.50-$3.70=$14.80
Now that you have the new price, you need to find 6.75% of it to get the sales tax, so you multiply $14.80 by 6.75%, which is 0.0675 as a decimal.
$14.80x0.0675=$0.999 or $1
Now you add the sales tax to $14.80
$14.80+$1=$15.80 or $14.80+$0.999=$15.799
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)
