# Gradient of f(x,y)

• April 30th 2008, 03:18 AM
taurus
find the gradient of
f(x, y) = 7(x^5)(y^4) − 9(x^3)(y^8)
Please enter your answer as a row vector, using the list syntax.

Now what i have done is below which i dont think is right for the question of row vector. Could someone help?

(35*x^4*y^4 - 27*x^2*y^8)i + (28*x^5*y^3 - 72*x^3*y^7)j
• April 30th 2008, 03:24 AM
taurus
Actually its fine, i found out what to do. thanks anyway
• April 30th 2008, 03:28 AM
Moo
Hello,

Quote:

Originally Posted by taurus
find the gradient of
f(x, y) = 7(x^5)(y^4) − 9(x^3)(y^8)
Please enter your answer as a row vector, using the list syntax.

Now what i have done is below which i dont think is right for the question of row vector. Could someone help?

(35*x^4*y^4 - 27*x^2*y^8)i + (28*x^5*y^3 - 72*x^3*y^7)j

Your result is correct, but you're asked a row vector, which will be :

$\overrightarrow{grad}(f)=\left(35x^4y^4-27x^2y^8 \ , \ 28x^5y^3-72x^3y^7\right)$