I need to prove the following: 1) (1 + cotX)/(cosecX) - (secX)/(tanX + cotA) = cos and 2) (5 - 7cos^2X)(sin^2X) = 5 - 2cot^2X
Follow Math Help Forum on Facebook and Google+
Originally Posted by Gilesy I need to prove the following: 1) (1 + cotX)/(cosecX) - (secX)/(tanX + cotA) = cos and 2) (5 - 7cos^2X)(sin^2X) = 5 - 2cot^2X Replace all trig functions by the equivalent in terms of sines and cosines and simplify. RonL
Originally Posted by Gilesy [snip] 2) (5 - 7cos^2X)(sin^2X) = 5 - 2cot^2X Note that the numerator can be written as $\displaystyle 5 - 5 \cos^2 x - 2 \cos^2 x = 5(1 - \cos^2 x) - 2 \cos^2 x = 5 \sin^2 x - 2 \cos^2 x$.
View Tag Cloud