Question 5(a)
[Maximum number: 4]
A curve has equation . The curve has exactly one stationary point P.
Find and hence show that the x-coordinate of P satisfies the equation .

Practise differentiating exponential, logarithmic, trigonometric, inverse-tangent, implicit and parametric curves and applying derivatives to exact gradients and stationary points.
A curve has equation y=1+3x1+e2x. The curve has exactly one stationary point P.
Find dxdy and hence show that the x-coordinate of P satisfies the equation x=61+21e−2x.
A curve has parametric equations
for 0<θ<21π.
Show that dxdy=6cos5θ−5cos3θ.
(b)Find the equation of the normal to the curve at the point where it crosses the x-axis.Give your answer in the form y=m x+c ,where m and c are exact constants.
The equation of a curve is y=tan−1(4x).
Find the exact values of x when the gradient of the curve is 41.