Question

Calculus I- The equation of the tangent to the curve x^2=4y at the point on the curve where x=-2 is...

Answer 1

@tkhunny

Answer 2

@amistre64

Answer 3

and you thoughts about this are?

Answer 4

to create a line, we can use a point and a slope. how do we define these parts?

Answer 5

y=x^2/4

Answer 6

point is (-2, 1) i believe

Answer 7

good, and the slope?

Answer 8

x/2 is the slope

Answer 9

m = x/2, for a given x yes

Answer 10

so how do we find the tangent of the curve at this point? is it just y=-1?

Answer 11

the slope is -1

Answer 12

what line equation formats do we know of?

Answer 13

uh....y=mx+b

Answer 14

y = mx + b is good, but only if we know a specific point, the y intercept

lets use point slope format, since we have a general point and a slope

y - p1 = m(x-px)

Answer 15

ugh ... not enough mt dew yet

y - py = m(x-px)

Answer 16

ok

Answer 17

is that an: ok it makes sense? or an: ok now what do i do?

Answer 18

ok now what do i do?

Answer 19

plug in the values that we found

m = -1 the point (px,py) = (-2,1)

Answer 20

y-1=-1(x+2)

Answer 21

yep

Answer 22

y=-x-1

Answer 23

so x+y+1=0

Answer 24

thank you!

Answer 25

as a dbl chk

http://www.wolframalpha.com/input/?i=y%3Dx%5E2%2F4%2C+y%3D-%28x%2B2%29%2B1

youre welcome :)