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How to find the derivative of arctan(x)

Let y = arctan(x). Then x = tan(y). Differentiate using the chain rule and rearrange: d(x)/dx = d(tany)/dx So 1 = sec^2(y) * dy/dx dy/dx = 1/sec^2(y) But from identity sin^2(y) + cos^2(y) = 1 We can derive, ...
MR
Answered by Matthew R. • Maths tutor
15316 Views

What are some ways to learn noun genders in Spanish?

As all Spanish nouns are classified as either masculine and feminine, I have found several ways of learning how to easily remember and be able to recognise the gender of a noun when I see it written down or ...
HT
Answered by Henry T. • Spanish tutor
3223 Views

How do I do this question: A small stone is projected vertically upwards from the point A with speed 11.2 m/s. Find the maximum height above A reached by the stone.

[Draw Diagram] We are given the inital velocity u=11.2m/s and we know the acceleration due to gravity is 9.8m/s^2. We need to find the distance 's'. When the stone is at its highest point the velocity will b...
LW
Answered by Luke W. • Maths tutor
6494 Views

What are some tips for writing an essay in French?

There are several things I try to bear in mind when coming to write a French essay- some which apply to essay writing in general, and others specific to writing in French. Firstly I have found that it is imp...
HT
Answered by Henry T. • French tutor
9308 Views

In a sentence using the ‘passé composé’, when do we agree the past participle with the subject and the direct object?

With the subject: The past participle only agrees with the subject of the sentence when the auxiliary (auxiliaire in French) is the verb ‘être’. When the auxiliary ‘avoir’ is used, the past participle never ...
AP
Answered by Aliette P. • French tutor
4633 Views