Recall that
d/dx sech(x) = - sech(x) tanh(x)
d/dx tan⁻¹(x) = 1/(1 + x²)
Then by the chain rule,
dy/dx = - sech(x) tanh(x) / (1 + x²)
I think the answer is b. cos(pi theta)= -0.6
This is a linear function, of the kind y = mx + b
where x is the number of visit, b is the weight when x = 0, and m is the predicted change of weight for every visit.
m = - 4 ounces / visit, which must be converted to pounds (the negative sign indicates that the change is a decrease)
1 lb = 16 ounces = 4 ounces = 0.25 lb
Then m = - 0.25 lb / visit.
Now, for x = 1, y = 126 => 126 = - 0.25(1) + b => b = 126 + 0.25 = 126.25
Then the function is y = 126.25 - 0.25x
Now round to the nearest tenth:
y = 126.3 - 0.3x
Answer: y = 126.3 - 0.3x
Answer: B (2,1)
You know what y is (x-1) so you substitute that for y in the other equation.
3x+ ((4)(x-1))=10
3x+4x-4=10
7x=14
x=2
Then put x=2 into y=x-1
y=2-1
y=1