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Mathematics 17 Online
OpenStudy (anonymous):

precalculus question love help!!!

OpenStudy (anonymous):

OpenStudy (anonymous):

4sin(x) + 4cos^2(x) = 4 sin(x) + cos^2(x) = 1 sin(x) + 1-sin^2(x) = 1 sin^2(x) -sin(x) = 0 sin(x) [ sin(x) -1 ] = 0 x = 0, pi/2

OpenStudy (campbell_st):

lol... use sin^2 + cos^2 = 1 then cos^2 = 1 - sin^2 substitute it into your equation 4sin(x) + 4(1 - sin^2(x)) = 4 divide by 4 sin(x) + 1 - sin^2(x) = 1 or sin(x) - sin^2(x) = 0 factorise sin(x)(1 - sin(x)) = 0 solutions are when sin(x) = 0 or 1 gee I think I've done this question before

OpenStudy (anonymous):

so is the solution 0, pi/2 or 0, 1

OpenStudy (anonymous):

and thanks for all your help today campbell

OpenStudy (anonymous):

The answers occur when sin(x) is 0, 1 The answers ARE 0, pi/2

OpenStudy (campbell_st):

the domain for t is [0, 2pi] so you need to include pi and 2pi... as sin(t) = 0 at those points... but I'm not sure on the answer restrictions

OpenStudy (anonymous):

it actually says 0,pi/2 arent correct so are those the answers for just throughout that first rotation? because the domain is 2pi are there two more solutions ?

OpenStudy (campbell_st):

the way I read the question, there are 4 answers, 0, pi/2, pi, 2pi

OpenStudy (anonymous):

[0, 2pi) means that 2pi cannot be included in the answer choice set

OpenStudy (anonymous):

oh shoot yeah i forgot about pi

OpenStudy (anonymous):

So the answers are 0, pi/2, pi

OpenStudy (campbell_st):

ok thanks wombat... so exclude 2pi... its 0, pi/2 and pi

OpenStudy (anonymous):

YALL ROCK!

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