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maths P1 nov 2008 why -ve ????
- Thread starter crash250
- Start date
as u can see in front of the cos(X) there is a minus sign hence when finding maximum value u will take cos(X) as -1 so the minius goes with the minus and become positve
a-(b*-1) which will be a+b=10
where as when cos (X) is 1
a-(b*1) which will be a-b=-2
a-(b*-1) which will be a+b=10
where as when cos (X) is 1
a-(b*1) which will be a-b=-2
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You can see that in the equation, the variable x affects the value of -b cos(x) only. For cos(sth), the value should be >=0 and <= 1.
So in the equation, 0 <= b cos(x) <= b.
Hence 0 >= -b cos(x) >= -b.
Maximum 10, so a + 0 = 10, a = 10
Minimum -2, then a + (-b) = 2, b = 12
So in the equation, 0 <= b cos(x) <= b.
Hence 0 >= -b cos(x) >= -b.
Maximum 10, so a + 0 = 10, a = 10
Minimum -2, then a + (-b) = 2, b = 12