0 votes 0 votes The equations $x=a \cos \theta + b \sin \theta$ and $y=a \sin \theta + b \cos \theta$, $( 0 \leq \theta \leq 2 \pi$ and $a,b$ are arbitrary constants) represent a circle a parabola an ellipse a hyperbola Quantitative Aptitude isi2015-dcg quantitative-aptitude trigonometry geometry + – gatecse asked Sep 18, 2019 • retagged Nov 14, 2019 by Lakshman Bhaiya gatecse 723 views answer comment Share Follow See all 13 Comments See all 13 13 Comments reply `JEET commented Sep 23, 2019 reply Follow Share A?? 0 votes 0 votes ankitgupta.1729 commented Oct 1, 2019 reply Follow Share how ? 0 votes 0 votes `JEET commented Oct 1, 2019 reply Follow Share Just square and add $x$ and $y$. 0 votes 0 votes `JEET commented Oct 1, 2019 reply Follow Share @ankitgupta.1729 Is that correct ?? 0 votes 0 votes ankitgupta.1729 commented Oct 1, 2019 reply Follow Share but $\theta$ will not be removed.. right ? 1 votes 1 votes `JEET commented Oct 1, 2019 reply Follow Share oh Sorry I didn't see properly. I thought there is a "minus" sign in the second question, as that is the popular equation. Thanks. 1 votes 1 votes ankitgupta.1729 commented Oct 1, 2019 reply Follow Share if $y=asin\theta - bcos\theta$ then it will be correct. Here, $\theta$ is a parameter and parametric equation are written here, So we have to eliminate $\theta$ . 0 votes 0 votes `JEET commented Oct 1, 2019 reply Follow Share So, what should be the answer finally? 0 votes 0 votes ankitgupta.1729 commented Oct 1, 2019 reply Follow Share bhai. don't know..I am not getting any method to eliminate $\theta$ here. 0 votes 0 votes `JEET commented Oct 1, 2019 reply Follow Share Yeah but I got. $x^2 + y^2 = 4ab\sin\theta\cos\theta = 2ab.\sin2\theta$ From here we can do. What do you think?? 0 votes 0 votes ankitgupta.1729 commented Oct 1, 2019 reply Follow Share I don't think, we can replace $\theta$ here 1 votes 1 votes `JEET commented Oct 1, 2019 reply Follow Share I am feeling the same as well. I hope the question is correct then. 2 votes 2 votes `JEET commented Nov 14, 2019 reply Follow Share @gatecse Please check this question once. Is it typed correctly? 0 votes 0 votes Please log in or register to add a comment.