Question

Find the value of the constant c for which the line y=2x+c is a tangent to the curve y^2 =4x.

Answer 1

see

Answer 2

the idea is that you need to equate both equations as they intersect. Tangent gives equal roots so you both b^2-4ac=0

Answer 3

It's the right step, but the answer says c= 1/2...?

Answer 4

yes sorry i wrote -16c instead of -32c

you will get now c=1/2

Answer 5

why would it be -32c?

Answer 6

Oh, I got it. Thanks :)