Question

Eliminate the parameter.

x = 5 cos t, y = 5 sin t

Answer 1

Same as before, what would you do this time?

Answer 2

hint: square both sides and add the equations together

Answer 3

why do this? because you can take advantage of the fact that

sin^2(x) + cos^2(x) = 1

Answer 4

so it would be x^2=25t?

Answer 5

no not quite

Answer 6

Think of your pathagoriean identities. And remember to factor out any constants...

Answer 7

x = 5*cos(t)

x^2 = (5*cos(t))^2

x^2 = (5^2)*(cos(t))^2

x^2 = 25cos^2(t)

Answer 8

do the same for y

Answer 9

so for y it would be
y = 5*sin(t)
y^2 = (5*sin(t))^2
y^2 = (5^2)*(sin(t))^2
y^2 = 25sin^2(t)

Answer 10

yep

Answer 11

now add the two equations to get

x^2 + y^2 = 25cos^2(t) + 25sin^2(t)

Answer 12

see where this is going?

Answer 13

x^2 + y^2 = 25[cos^2 (t) + sin^2(t) ] = 25

Answer 14

so the answer would be what you put? @deepconcept

Answer 15

that's not the final answer, but that's leading up to it

Answer 16

final answer is x^2 + y^2 = 25
as cos^2(t) + sin^2 (t) = 1

Answer 17

Thank you guys so much!!!

Answer 18

you're welcome