What is a double angle identity to find the exact value of cos? Group of answer choices

cos⁡(2a)=〖cos〗^2⁡(a)+〖sin〗^2⁡(a)

cos⁡(2a)=〖cos〗^2⁡(a)

cos⁡(2a)=2 〖cos〗^2⁡(a)-1

cos⁡(2a)=〖2cos〗^2⁡(a)-2 〖sin〗^2⁡(a)

answer: ouch. thats difficult

step-by-step explanation:

answer

the correct answer is

explanation

the given function is

the excluded values are obtained by solving:

we factor to obtain:

the excluded values are

b. hannah is playing with her cousin at

answer is c

step-by-step explanation:

81/12=324/x

x=48