Find , when
Theorem: y and x are given in a different variable that is θ . We can find by finding and and then dividing them to get the required thing. = = eθ (cosθ + sinθ ) + (sinθ -cosθ )eθ ………..(1) {by using product rule, } = eθ (cosθ - sinθ ) + eθ (sinθ + cosθ ) …………….(2) {by using product rule, } Dividing (1) and (2), we get = =tanθ .