it's customary to actually write the exponent, ya know
x^2 = x squared
x^3 = x cubed, etc.
what you wrote would normally be considered 3x^-1 = 3/x
So. You have y = 3x^2 - 1
y' = 6x
so, where is 6x = 3?
x = 1/2
so y = 3*(1/2)^2 - 1 = -1/4
That makes the point (1/2, -1/4)
Just to be sure, the tangent line should be
y = 3 (x - 1/2)-1/4
The graph here shows we are correct.
www.wolframalpha.com/input/?i=plot+y%3D3x%5E2-1%2C+y%3D3%28x-1%2F2%29-1%2F4
What is the coordinates of the point on the curve y=3x^-1 where the gradient is 3.
The sign ^ means square
1 answer
3 answers