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Question
Find the value of sin 30° + cos 60°.
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Solution
sin 30° + cos 60° = `1/2 + 1/2`
= `(1 + 1)/2`
= `2/2`
= 1
∴ sin 30° + cos 60° = 1
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Solution:
In Δ ABC, ∠ABC = 90°, ∠C = θ°
AB2 + BC2 = `square` .....(Pythagoras theorem)
Divide both sides by AC2
`"AB"^2/"AC"^2 + "BC"^2/"AC"^2 = "AC"^2/"AC"^2`
∴ `("AB"^2/"AC"^2) + ("BC"^2/"AC"^2) = 1`
But `"AB"/"AC" = square and "BC"/"AC" = square`
∴ `sin^2 theta + cos^2 theta = square`
