# integrating a parametric questionWatch

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#1
x=5cost y=3sin2t

need to integrate -15sin^2tcost
-the limits for x are 5 and 0.
-I changed the limits to 0 and pi/2
0
1 week ago
#2
(Original post by theweirdo)
x=5cost y=3sin2t

need to integrate -15sin^2tcost
-the limits for x are 5 and 0.
-I changed the limits to 0 and pi/2
1
#3
(Original post by mqb2766)
Yup
0
5 days ago
#4
(Original post by theweirdo)
Yup
Assuming you used the double angle formula for sin2t in the third line, I think you didn't multiply the 15 by 2
1
5 days ago
#5
(Original post by theweirdo)
x=5cost y=3sin2t

need to integrate -15sin^2tcost
-the limits for x are 5 and 0.
-I changed the limits to 0 and pi/2
Is it because you are meant to multiply your answer by 2 because you found the area above the x-axis only? can you upload the full question please.
1
#6
(Original post by GreenDeath)
Is it because you are meant to multiply your answer by 2 because you found the area above the x-axis only? can you upload the full question please.
yup, sure
0
5 days ago
#7
That's what I think OP did wrong as well.
(Original post by I'm God)
Assuming you used the double angle formula for sin2t in the third line, I think you didn't multiply the 15 by 2
1
#8
(Original post by I'm God)
Assuming you used the double angle formula for sin2t in the third line, I think you didn't multiply the 15 by 2
omg yes i did forget to do that!
i didn't see that! i'll try the question again
thank you
0
5 days ago
#9
Same should be -30sin^2tcost
(Original post by hahaweeb)
That's what I think OP did wrong as well.
1
#10
(Original post by B0redBrioche)
Same should be -30sin^2tcost
(Original post by hahaweeb)
That's what I think OP did wrong as well.
(Original post by I'm God)
Assuming you used the double angle formula for sin2t in the third line, I think you didn't multiply the 15 by 2
tried this and it worked thank you!
0
5 days ago
#11
(Original post by theweirdo)
tried this and it worked thank you!
Nice!
No worries mate
0
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