Was unsure as to how to go about answering these questions on my homework. Any help would be much appreciated

Solve for 0 x 360 , correct to 1 decimal place where necessary:

1.

a) 3 cos x - cosx = 0

b) 12 sin x - 5sinx - 2 = 0

2.

a) State the maximum value of 10 / 110 - 20x + x

**0**

# A few homework questions

Started by Gillz, Oct 01 2006 01:00 PM

4 replies to this topic

### #1

Posted 01 October 2006 - 01:00 PM

### #3

Posted 19 October 2006 - 10:41 PM

1. a) take out cosx as a common factor and this should give you

cosx(3cosx - 1) = 0

therefore cosx = 0 or 3cosx - 1 = 0

solve both equations

b) Let X = sinx

Rewrite equation 12X -5X - 2 = 0

Factorise to slove this equation

Then substitiute X = sinx and solve resultant trig equations

2) Complete the square for the expression 110 - 20x + x

to get the minimum value of the function f(x) = 110 - 20x + x

substitute this value into the fraction (i.e.make this value the denominator) to obtain the maximum value of the fraction

cosx(3cosx - 1) = 0

therefore cosx = 0 or 3cosx - 1 = 0

solve both equations

b) Let X = sinx

Rewrite equation 12X -5X - 2 = 0

Factorise to slove this equation

Then substitiute X = sinx and solve resultant trig equations

2) Complete the square for the expression 110 - 20x + x

to get the minimum value of the function f(x) = 110 - 20x + x

substitute this value into the fraction (i.e.make this value the denominator) to obtain the maximum value of the fraction

### #4

Posted 19 October 2006 - 11:02 PM

Bit late for a reply now.

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### #5

Posted 20 October 2006 - 01:58 PM

Just joined the forum. Trying out the process of replying to a problem.

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