turning pt?

[lacoste]

For the function f : (–∞, a)→ R, f(x)= x² + 2x
a. find the maximum value of a such that the inverse function f ^–1 exists.


how do you find the turning pt from that graph, ive forgotten?

[d0minicz]

derive it
let it equal 0 and sub that x value into original

[lacoste]

thanks

[ed_saifa]

Complete the square

[lacoste]

thanks ed saifa and dominicz

[QuantumJG]

For the function f : (–∞, a)→ R, f(x)= x² + 2x
a. find the maximum value of a such that the inverse function f ^–1 exists.


how do you find the turning pt from that graph, ive forgotten?

simple differentiate the function, set f'(x)=0 and solve!

f'(x) = 2x + 2

let f'(x) = 0 => x + 1 = 0 => x =-1 = a_max

i.e. f ^–1 exists iff a -1

[lacoste]

cheers