Raw Transcript

This video is on trig identities derivatives and integrals as they apply to trig functions and let’s get started we have um second alpha allows you to put letters into the calculator or the screen I_n_d_e_x alpha 8 closed parentheses, closed parentheses tells you uh… for calculus and up comes a menu and we’re going are you can go up and go down in the last part of the alphabet and we want to go maybe trig and half angle formulas for that pretty interesting program you can scroll down and choose whatever you want for instance lets start something easy like cosine of x and you notice the derivative of cosine of x minus sign of x and the integral of cosine of x is sine of x plus c identities or one over secant cotangent sine of x sine of x over tangent of x double angle formula cosine of x equals sine of two x divided by two sin of x these are all things that come up in calculus and you either memorize them or you know them your a genius or like me would trigger my mind once i get away from sin or cosine and um… was able to add the identity to come back and do some problems lets take for instance the next one cosine squared of x half angle formula his equal to one-plus cosine two x divided by two pythagorean identity is one minus sine squared x derivative you have the original function cosine squared of x which is really cosine of x times cosine of x and so you have the product rule here which we use f prime then would be cosine of x times the derivative of cosine of x plus the derivative cosine of x times cosine of x and it works out to these uh… cosine of x minus sign of x et cetera et-cetera and that’s how they get the derivative of two sine of x cosine of x pretty interesting lets do one more.