Question

in ∆ABC if sinA: sinB : sinC = 1:2:2, then find the value of COSA.

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Answer 1

Answer:

As it's said to find the value , it simply means the numerical answer and ofcourse, not in the form of any variable.....As I earlier did, by sqrt.(1-sin²A) = sqrt.(1-x²)

but you see, it didn't give the value....

so definitely it's wrong way of thinking ......therefore , refer the required solution in this pic....