How is the value of sin (90+30) equal to cos (30)? - Quora

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What is sin if cos is 12/13? - Quora

How is the value of sin (90+30) equal to cos (30)? - Quora

If sin (x+30)° = cos 40°, what is the value of x? - Quora

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What is 2 sin 60 cos 90 + cos 30 2 sin 90? - Quora

What is the value of sin45°×cos30°+cos45°×sin30°? - Quora

Is this possible: cos A + sin A = 1? - Quora