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Find the stationary points on the curve y = x^3 + 3x^2 - 9x - 4

A stationary point is where the gradient is exactly zero - the curve is neither increasing or decreasing. This means that we need to differentiate y to find dy/dx and then set this equal to 0. Doing this, us...
RR
Answered by Richard R. • Maths tutor
17322 Views

By writing tan x as sin x cos x , use the quotient rule to show that d dx ðtan xÞ ¼ sec2 x .

First write tanx as sinx/cosx as it is always helpful to use what additional information the question gives you. It says we must use the quotient rule to calculate the result so it is also a good idea to wri...
DB
Answered by Daniel B. • Maths tutor
7814 Views

Find the integral on ln(x).

Integrate by parts, identifying that dv/dx = 1, u = ln(x) and therefore v = x and du/dx = 1/x. Sub into the parts equation to find the answer to be xln(x) - x + c.
DO
Answered by Daniel O. • Maths tutor
4056 Views

Sine Rule

The sine rule is a very powerful tool used in mathematics to calculate unknown sides and angles of triangles when we only know some of the information. For example if we have a triangle and we know two angle...
HG
Answered by Hugo G. • Maths tutor
6108 Views

I can't figure out this question to do with VAT. VAT is charged at 20%. A TV is for sale for £650 inc. VAT in Good Electronics and the same TV is for sale £495 exc. VAT in Wright's Electricals, where is it cheaper?

I can't figure out this question to do with VAT. VAT is charged at 20%. A TV is for sale for £650 inc. VAT in Good Electronics and the same TV is for sale £495 exc. VAT in Wright's Electricals, where is it c...
WH
Answered by William H. • Maths tutor
5950 Views