00:01
Hi, in this question, we have been given a function z is equal to x log y plus x raised to the power 4 y plus 2 and this is the equation of a surface and we have been given a point whose coordinates are x0, y0, z0 and the corresponding values are 2, 1 and 80.
00:31
Then we need to find the equation of tangent at this point.
00:35
So, we can write this g is equal to a function of x and y and this is equal to x times log y plus x raised to the power 4 times y plus 2.
00:50
So, if we partially differentiate this, so we will get fx equal to del del x of x log y plus x raised to the power 4 times y plus 2.
01:05
So, this will be equal to here we are partially differentiating.
01:09
So, we will keep y as a constant.
01:12
So, this will be log y plus 4 x cube y plus 0.
01:18
So, we can write partial derivative of f with respect to x at 2, 1, 80 is equal to log 1 plus 4 times x cube that is 2 cube multiplied by 1.
01:35
So, as we know that the value of log 1 is 0.
01:39
So, this will be 4 times 8.
01:44
So, this is fx at 2, 1, 80 and this is equal to 32.
01:50
Now, similarly, we will find partial derivative of f with respect to y.
01:55
So, we can write del del y of x log y plus x raised to the power 4 y plus 2...