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Find the inverse of a 3x3 matrix

There are 4 key steps to this question. (i) calculate the matrix of minors: you want to find the determinant of each entry and this forms a new matrix. (ii) convert this into a matrix of cofactors: this is a...
JR
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A ladder 5m long is leaning up against a wall. The foot of the ladder is 3m from the wall. How high up the wall does the ladder reach?

Think about which mathematical theorem you might want to use for this question (Pythagoras: a 2 + b 2 = c 2 ) Draw a diagram of the situation described, and write down the equation you think you should use. ...
JR
Answered by Josie R. • Maths tutor
15608 Views

How might you use sound waves to smash a glass? What are other examples of resonance in everyday life?

The natural frequency of a glass can be found by tapping it or making it 'sing' (running a wet finger around the top of the glass till it sings a note. If you emit sound waves at this frequency in the direct...
JR
Answered by Josie R. • Physics tutor
2792 Views

Why is the sky blue?

Light from the sun is white. As it passes through the Earth's atmosphere, the different wavelengths of white light (i.e. the visible spectrum of colours) are scattered by gas and dust particles. Colours with...
JR
Answered by Josie R. • Physics tutor
5964 Views

How do you conjugate the present subjunctive mode?

For regular verbs, these conjugations are relatively easy - the way I remember it is that you switch the endings of AR verbs with those of ER/IR verbs in the indicative. e.g. present indicative com er : yo c...
AM
Answered by Ashley M. • Spanish tutor
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