/sci/ - Science & Math

[Anonymous No.2654802]

the curve y = 2+x - x^ 2 has a tangent at p (1,2)

the tangent meets the x and y axis at l and m

find the coordinates?

any help?

i tried finding the derivative subbing the coordinates in to get -3, form an equation and solve it but its wrong. any help pls?

[Anonymous No.2654828]

derivate your function

Now evaluate the derivated function at x=1. You just found the slope of the curve in (1,2)

The tangent is f(x)=a*x+b with a the slope you just found and b a constant. The only unknown value here is b, so you just need one equation to solve it: just say that the tangent equals the original function at (1,2).

[Anonymous No.2654864]

what about l andm

[Anonymous No.2654894]

y = 2 + x - x^2

y' = 1 - 2x

1 - 2(1) = -1
y = -1x + b

2 = -1(1) + b
b = 3

y = -1(0) + 3
y = 3

0 = -1x + 3
x = 3

L(3,0)
M(0,3)

[Anonymous No.2654964]

>>2654894


so i cant use y -y1 = m (x - x1)

thnx for help