Question

if f(x,y)=arctan(xy), compute an approximate value of f(0.9,-1.2)? @Mathematics

Answer 1

The first thing you need to do is compute the product of x and y and the second thing you need to do is take the arc tangent of it.

So the product 0.9 * -1.2 = -1.08.

Then the arctan(-1.08) = -0.824.

Check my math yourself.

Answer 2

solve it using taylor's theorem?

Answer 3

just use the calculator?

Answer 4

I think the object of the question is to get one to see that the stated function can be viewed as a composition of g(z) = xy and h(z)= arctan(z). Then f(x, y) = h(g(z)). Not sure what the next step is, though. :)

Answer 5

.9 is about 1. -1.2 is about -1. So arctan(.9*(-1.2)) is about arctan(-1), which is -pi/4, roughly -.78. Now whether that is "approximately" enough...