C1 – Integration Summary Integration is the process of finding a function from its derivative. dy dx = axn y= a n1 x n1 + c where c is an arbitrary constant that can only be found with further information. Increase the power by one and divide by new power. Make sure you do not forget + c in indefinite integration. Notation: ax dx = n a n1 x n1 + c Definite integration: Integration is the process of finding a function from its derivative. dy dx = axn y = b f ( x)dx f ( x)a f (b) f (a) a a n1 x n1 + c where c is an arbitrary constant that can only be found with further information. Increase the power by one and divide by new power. Make sure you do not forget + c in indefinite integration. Notation: Make sure you do not forget dx as part of the notation. b C1 – Integration Summary ax dx = n a n1 x n1 + c Make sure you do not forget dx as part of the notation. b Definite integration: f ( x)dx f ( x) b a When finding a definite integral writing + c is not necessary as it will cancel out. Make sure your integral goes in square brackets with the limits on the right hand side. Make sure you substitute in the top number first. Unless stated otherwise, the larger number goes on top. The area of the region bounded by the curve y = f(x), the x axis and the When finding a definite integral writing + c is not necessary as it will cancel out. Make sure your integral goes in square brackets with the limits on the right hand side. Make sure you substitute in the top number first. Unless stated otherwise, the larger number goes on top. The area of the region bounded by the curve y = f(x), the x axis and the b lines x = a and x = b is given by f (b) f (a) a b f ( x)dx . a If the region is below the x axis the integration will give a negative value. The area is the positive value of the integral. If the region is partly above and partly below the x axis evaluate as two separate regions then add together the separate areas. To find the are between two curves y = f(x) and y = g(x): method 1) find area under each curve and subtract results method 2) find f(x) – g(x) and integrate the result The limits of the integration are the x coordinates of the points where y = f(x) meets y = g(x). In method 2 f(x) should be the curve on top, otherwise the result will be the negative value of the area. lines x = a and x = b is given by f ( x)dx . a If the region is below the x axis the integration will give a negative value. The area is the positive value of the integral. If the region is partly above and partly below the x axis evaluate as two separate regions then add together the separate areas. To find the are between two curves y = f(x) and y = g(x): method 1) find area under each curve and subtract results method 2) find f(x) – g(x) and integrate the result The limits of the integration are the x coordinates of the points where y = f(x) meets y = g(x). In method 2 f(x) should be the curve on top, otherwise the result will be the negative value of the area.