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Mathematics 22 Online
OpenStudy (anonymous):

Evaluate the integral by making the given substitution

OpenStudy (anonymous):

\[\int\limits_{?}^{?}(2\sin(\sqrt{x}))\div \sqrt{x} u=\sqrt{x}\]

OpenStudy (anonymous):

What's the given substitution?

OpenStudy (anonymous):

u=sqrt (x)

OpenStudy (anonymous):

u=sqrt(x)

OpenStudy (anonymous):

you get integral sin(u) du

OpenStudy (anonymous):

= -cos(sqrt(x) ) + constant

OpenStudy (anonymous):

nah i think thats wrong

OpenStudy (anonymous):

was doing too many steps in my head I think

OpenStudy (anonymous):

there should be a 4 -4cos( sqrt(x)) +C

OpenStudy (anonymous):

differentiate that and it works out

OpenStudy (anonymous):

where did you get the -4?

OpenStudy (amistre64):

2sin(sqrt(x)) {S} ---------- dx ; u = sqrt(x) sqrt(x) Dx(u = sqrt(x)) du = 1/2sqrt(x) dx dx = 2sqrt(x) du ; but since u = sqrt(x) we get: dx = 2u du ................................ 2 sin(u) 2u {S} --------- du ; the u up top and bottom cancel u {S} 2 sin(u) 2 du ; now 2*2 = 4 so rewrite as: {S} 4 sin(u) du ; pull out the constant (4) 4 {S} sin(u) du and integrate

OpenStudy (amistre64):

sin(u) integrates up to -cos(u) soo... 4 (-cos(u)) + C -4 cos(sqrt(x)) + C

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