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How would I find the indefinite integral of x*cos(x) dx

Use integration by parts, by setting u=x and cos(x)=dv/dx. The final result should be xsinx + cosx + c.
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Answered by Ed S. Maths tutor
4951 Views

integrate (4cos^4 x -4cos^2x+1)^1/2

we must integrate (4cos 4 x-4cos 2 x+1) 1/2 factorise first ((2cos 2 x-1) 2 ) 1/2 this becomes (2cos 2 x-1)which equals cos 2xthe integral of cos 2x is1/2 sin 2x + C
DW
Answered by Dominic W. Maths tutor
3994 Views

What is the lowest common multiple and the highest common factor of 120 and 150?

To approach a problem like this, we must first break down our number into a multiplication of prime factors (i.e. we can make our number by multiplying numbers 2,3,5,7 etc together). This is best done with a...
DW
Answered by Dominic W. Maths tutor
7177 Views

How do you factorise a quadratic equation into the form (x+A)(x+B), for example x²+x-6 =0?

Quadratic equations are always given in the form a x 2 + b x + c . One way of solving (finding values of x) and therefore factorising is to use the quadratic formula which is :x = −b ± √(b 2 − 4ac)/ 2a ,usin...
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Answered by India J. Maths tutor
3226 Views

3 teas and 2 coffees have a total cost of £7.80 5 teas and 4 coffees have a total cost of £14.20 Work out the cost of one tea and the cost of one coffee.

You make simultaneous equations. 1.) 3T+2C=7.82.) 5T+4C=14.2Then you make either the C or the T coefficient equal in both equations. I choose to make the C coefficients the same. So I multiplied equation 1 b...
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Answered by Dan S. Maths tutor
6659 Views