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For any real `t ,x=1/2(e^t+e^(-t)),y=1/2(e^t-e^(-t))`is a point on the hyperbola `x^2-y^2=1`Show that the area bounded by the hyperbola and the lines joining itscentre to the points corresponding to `t_1a n d-t_1`is`t_1dot` |
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Answer» It is a point on hyperbola `x^(2)-y^(2)=1`. Area `(PQRP) = 2 underset(1)overset(e^(t_(1))+e^(-t_(1)))overset(2)(int)ydx = 2 underset(1)overset(e^(t_(1))+e^(-t_(1)))overset(2)(int)sqrt(x^(2)-1)dx` `= 2[x/2sqrt(x^(2)-1)-1/2l(x+sqrt(x^(2)-1))]_(1)^(e^(t_(1))+e^(-t_(1))) = (e^(2t_(1))-e^(2t_(1)))/(4)-t_(1)` Area of `DeltaOPQ = 2 xx 1/2((e^(t_(1))+e^(t_(1)))/(2))((e^(t_(1))-e^(t_(1)))/(2)) = (e^(2t_(1))-e^(-2t_(1)))/(4)` `:.` Required area = area `DeltaOPQ` - area `(PQRP) = t_(1)`. (b) If `g(y) le 0` for `in [c,d]` then area bounded by curve `x = g(y)` and y-axis between abscissa `y = c`, and `-underset(y=c)overset(d)intg(y)dy` |
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