Question

A function of three variables is given by, f (x,y,t) = x3y2sin t + 4x2t + 5yt2 + 4xycos t Find ft (3.44,0.58,8.1) giving your answer to 3 decimal places.

anybody please help me... thanks a million... got stuck with this qns..

Answer 1

I am not certain what your ft means.

f((3.44,0.58,8.1)= ans obtained by putting in x,y, t into the equation. This is not a calculator friendly punch in, paste this in your google search window
(3.44^3)*((0.58)^2)*sin (8.1) + 4*(3.44)^2*(8.1) + 5(0.58)(8.1)^2 + 4*(3.44)*(0.58)*cos(8.1=

CHECK IT. The only issues I question what units is t in? radians, degrees, or what?

Answer 2

It just occured to me, you <i>might</i> have meant ft the partial derivative of f with respect to t. That is not what is above.

Answer 3

ft = f(t)
t should be in radians mode..

Answer 4

f(t) is meaningless since f is a function of (x,y,t). If you want

∂f/∂t then that just think of x and y as constants:

f(x,y,t) = x^3 y^2 sin t + 4x^2 t + 5yt^2 + 4xycos t

∂f/∂t = x^3 y^2 cos t + 4x^2 + 10yt - 4xy sin t
(3.44,0.58,8.1)
= 3.44^2*0.58^2 cos(8.1) + 4*3.44^2 + 10*0.58*8.1 - 4*3.44*0.58*sin(8.1)
= 97.131