Example 2 Find the equation of the tangent to the circle
x + y2 + 4x - 10y = 12 at the point (3, 1).

-5x + 4y = -11.

Step-by-step explanation:

If it's a circle then it must be x^2 not x.

x^2 + y^2 + 4x - 10y = 12

Using implicit differentiation:

2x + 2y y' + 4 - 10 y' = 0

y'( 2y - 10) = -2x - 4

y' = (-2x - 4)/(2y - 10)

y' = (-x - 2) / (y - 5) = the slope of the tangent.

At  (3, 1),  y' = (-3-2) / (1 - 5)

=  5/4.

So the required equation is

y - y1 = 5/4(x - x1)  where x1 = 3 and y1 = 1.

y - 1 = 5/4(x - 3)

y = 5/4(x - 3) + 1

Multiply through by 4:

4y = 5(x - 3) + 4

4y = 5x - 15 + 4

In standard form the equation is:

-5x + 4y = -11.

linearly: 8560 bacteria

exponentially: approximately 75233 bacteria

step-by-step explanation:

assuming it is not exponential (we would have some really complicated logarithms), let's say it is linear. then, after 5 hours, it increased by 1200 bacteria, so every hour it increases by 240 bacteria. this means that after 19 hours, we get 19 * 240 + 4000 bacteria or 3800 + 760 + 4000 = 7800 + 760 = 8560 bacteria.

because it says round your answer, i will do this exponentially (with a calculator, of course). first, we need to find how much it multiplies by every hour, by taking the 5th root of 52/40 or 13/10. this is approximately 0.167. we still need to add 1 to this, because we are multiplying by that number, not adding that amount of the number. now, we just calculate 4000 * (1.167)^19. use a calculator to get approximately 75232.6, or 75233.

its d but looking at that hurts my eyes frfr

step-by-step explanation: