How many real solutions does the equation x7+ 14x5+ 16x3+ 30x – 560 = 0 have?
7
1
3
3
B.
1
x7+ 14x5+ 16x3+ 30x – 560 = 0
Let f(x) = x7+ 14x5+ 16x3+ 30x
⇒ f′(x) = 7x6+ 70x4+ 48x2+ 30 > 0 ∀ x.
∴ f (x) is an increasing function ∀ x.
I > 2/ 3 and J > 2
I < 2/ 3 and J < 2
I < 2/ 3 and J > 2
I < 2/ 3 and J > 2
The area of the plane region bounded by the curves x + 2y2= 0 and x + 3y2= 1 is equal to
5/3
1/3
2/3
2/3