Differentiate y=(x^2 + 2x)cos(3x)
Here we need to use the product rule in order to differentiate as we have two functions involved that are being multiplied together. Therefore we use the formula:dy/dx = u dv/dx + v du/dxFirst let u=(x^2 + 2x) and v=cos(3x)Therefore du/dx = 2x + 2 and dv/dx= -3sin(3x) (using chain rule)Next plug the values into the formula to get:dy/dx = (x^2 + 2x)(-3sin(3x)) + cos(3x)(2x + 2)
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