f(x)=3x+x3,x>0f(x) = 3x + x^3, \quad x > 0f(x)=3x+x3,x>0.
Differentiate to find f′(x)f'(x)f′(x).
Given that f′(x)=15f'(x) = 15f′(x)=15, find the value of xxx.
Practise Edexcel A Level Old Maths Differentiation and Integration 1 with exam-style questions for A Level Old Maths. 19 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.