- #1
AlonsoMcLaren
- 90
- 2
Homework Statement
If x=yz and y=2sin(y+z), find dx/dy
Homework Equations
Chain rule
The Attempt at a Solution
From y = 2sin(y+z) we get
dz/dy= (1-2cos(y+z))/(2cos(y+z))
dz/dy=((1/2)sec(y+z) - 1)
dx/dy = ∂x/∂y + ∂x/∂z dz/dy
= z + y ((1/2)sec(y+z) - 1)
= z - y - (1/2) sec(y+z)
But the answer is z-y+tan(y+z) (Mathematical methods in the physical sciences, Boas, Ch. 4 Sec 7 Problem 1)
What is going wrong?