A function is defined by f(x)= e^(x^2+4), all real x. Find inverse of f(x) and its domain.

Let f(x)=y: y = e^(x2+4); To find the inverse of a function, you need to find x in terms of y. In this case, you need to bring the exponent to the base. So in order to bring x2+4 from the power, take natural log of both sides so: ln(y) = ln(e^(x2+4)); ln(e^(a)) = a, where a is some function. This means that: ln(y) = x2+4; Now that x is a base, the algebra becomes simple. Isolate x; x2 = ln(y) - 4; Simplify; x = sqrt(ln(y) - 4); This is the inverse. However, to use the same terms as the original function let x = y and y = x, so; y = sqrt(ln(x)-4).

EC

Related Maths A Level answers

All answers ▸

Solve the differential equation : dy/dx - x^3 -5x = 0


The curve C has the equation ye ^(–2x) = 2x + y^2 . Find dy/dx in terms of x and y.


The Curve C has equation y = 3x^4 - 8x^3 -3. Find the first and second derivative w.r.t x and verify that y has a stationary point when x = 2. Determine the nature of this stationary point, giving a reason for your answer.


Solve the simultaneous equations: y = x - 2 and y^2 + x^2 = 10