**1. http://ift.tt/QCVyXV**

**2. ****grad**T = 10**i**+8**j**

**3. I can show the temperature is zero at point (1,-1) by just putting in x=1 and y=-1 to the function given in the image**

Hi ðŸ™‚

I have no idea what to do for finding the equation of the tangent part. If someone could help, then that would be great.

Thanks

http://ift.tt/QCVBmx