Answer:
The given expressions simplifies to tan (4x).
Step-by-step explanation:
Here, the given expression is : 
By TRIGONOMETRIC IDENTITY:

Putting this identity here, and taking A = 9 x, B = 5 x, we get

= tan(4x)
Hence, the given expressions simplifies to tan (4x).
Hi there!
In order to find the value of N, we'll need to set the value of the angle containing the variable n equal to 90. This is because in perpendicular lines, all angles are equal to 90.
WORK:
5n - 25 = 90
5n = 115
n = 23
The effective rate is calculated in the following way:

where r is the effective annual rate, i the interest rate, and n the number of compounding periods per year (for example, 12 for monthly compounding).
our compounding period is 2 since the bank pays us semiannually(two times per year) and our interest rate is 8%
so lets plug in numbers:
parallel when a=2
perpendicular when a=-1/2
20 I apologize if this is wrong