Question

I am missing something simple. How do I find the y-intercept of the tangent line to y=(1.2)/(3+7x)^-1/2 at (3,0.245)

Answer 1

well, i assume you've found the point it is tangent, yes?

Answer 2

then just create a formula for a line by y = mx + b

where m is the slope, and (x,y) is the point it is tangent

then solve for b and there ya go!

Answer 3

Thanks and should I derive thos equation, plug in (3) for X to find m?

Answer 4

yes, the derivative of the equation at the point (3,.0245) will tell you the slope

Answer 5

using the given point, the slope you're about to find, you can then solve for b using y = mx + b

Answer 6

I am having an issue solving for x in this equation.

Answer 7

you don't need to solve for x

Answer 8

to find the slope at the tangent point

1. take the derivative
2. plug in known (x,y) values
3. the answer is the slope

Answer 9

Thanks.....I knew I was missing something simple.

Answer 10

and you don't have to plug in the y value, by the way

just the x value

my bad

Answer 11

you'll be left with something like dy/dx = "number"

that number being the slope :)

Answer 12

i've gotta leave, so to re-cap:

1. find derivative
2. plug in x value
3. you'll be left with something like dy/dx = slope
4. using the given (x,y) point, and the slope you just found
5. plug them into y = mx+b and find b

Answer 13

good luck mate

Answer 14

1.derive the equation
2.plug in x
3.the answer is the slope
4.plug the slope, y and x to solve for b
5. let x=0 to find the y-intercept

Answer 15

Thanks