Question

Calculus Integral 3 to -3 Square root 9-x^2 dx

Answer 1

is this your integral?
\[\int\limits_{-3}^{3} \sqrt{9-x^2}dx\]

Answer 2

yes :o

Answer 3

looks it is a circle with the centre is (0,0) and its radius 3

Answer 4

so, we can solve without by integral

Answer 5

just use the formula the area of circle :
A = pi r^2
here r=3

Answer 6

oh so you just look at the graph

Answer 7

actually, yes :)

Answer 8

how is the answer 9pi/2 though? where does the 2 come from

Answer 9

It's not a circle by the way. It's a semi-circle.

Answer 10

oh yeah, it just a semi circle :)

Answer 11

btw, my assume is the curve
y = sqrt(9-x^2)
squaring to both sides :
y^2 = 9-x^2 or
x^2 + y^2 = 9
this, an equation of circle right ?

Answer 12

ok, this makes more sense now, thank you guys :)