its difficulty problem.

find dy/dx by implicit differentiation
1.4 cos x sin y = 1

2.tan(x/y)= x+y

1.) 4 cos x sin y = 1

2.) tan(x/y)= x+y

using product rule and chain rule,

4 (-sinx)(siny) + 4(cosx)(cosy y') = 0
y' = sinx*siny / cosx*cosy
= tanx * tany
--------------------
sec^2(x/y)*(1/y - x/y^2 * y') = 1 + y'

y*sec^2(x/y) - y^2
--------------------- = y'
y^2 + x*sec^2(x/y)

To find dy/dx by implicit differentiation, follow these steps:

1. Identify the equation that involves both x and y.
2. Apply the derivative to both sides of the equation with respect to x.
3. When taking the derivative of terms involving y, treat y as a function of x and use the chain rule to differentiate.
4. Solve the resulting equation for dy/dx.

Let's apply these steps to the given problems:

1. 1.4 cos x sin y = 1

Step 1: The equation that involves both x and y is 1.4 cos x sin y = 1.

Step 2: Take the derivative of both sides with respect to x:
d/dx (1.4 cos x sin y) = d/dx (1)

Step 3: Differentiate each term using the product rule and chain rule:
1.4[-sin x sin y dy/dx + cos x cos y] = 0

Step 4: Solve for dy/dx:
-1.4sin x sin y dy/dx + 1.4cos x cos y = 0
dy/dx = (1.4cos x cos y) / (1.4sin x sin y)
dy/dx = cos x / sin x
dy/dx = cot x

Therefore, the derivative dy/dx for the given equation is cot x.

2. tan(x/y) = x + y

Step 1: The equation that involves both x and y is tan(x/y) = x + y.

Step 2: Take the derivative of both sides with respect to x:
d/dx (tan (x/y)) = d/dx (x + y)

Step 3: Differentiate each term using the chain rule:
sec^2 (x/y) * (1/y) * d(x/y)/dx = 1

Step 4: Solve for dy/dx:
sec^2 (x/y) * (1/y) * (1/y) * dy/dx = 1
dy/dx = y^2 / (sec^2 (x/y) * (1/y))

Therefore, the derivative dy/dx for the given equation is y^2 / (sec^2 (x/y) * (1/y)).