Hello
cos ( x + pi/2) =cos(x)cos(pi/2)-sin(x) sin(pi/2)
= cos(x)×0-sin(x) ×1
cos ( x + pi/2) = - sin(x)
Make an equation
6p + p = 28
Combine like terms
7p = 28
Divide
p = 4
Solution: p = 4
Answer:

Step-by-step explanation:
Given
y jointly varies to x and z^2
Required
Find the equation
We start by writing out the variation;

Write as equation

Substitute values of x,y and z



Divide both sides by 7




Substitute k in 
