Explain, dont just give answers cuz i wanna know how to do it in the future? do i need to use a proportion?

Given tan∅=4/3 and π< ∅< (3π)/2; find cos2∅ a. -24/25 b. 24/25 c. -24/7 d. -7/25

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

Read the following two statements. then use the law of syllogism to draw a conclusion. if the tv is too loud, then it will give me a headache. if i have a headache, then i will have to rest.