Math CentralQuandaries & Queries


Question from Nazrul, a teacher:

How can I find the value of A if sinA-cosA=1 , where A is an acute angle.

Hi Nazrul.

Start by squaring both sides. You will get this:

sin²A - 2sinAcosA + cos²A = 1²

Now use these trig identities:

sin²A + cos²A = 1
2sinAcosA = sin2A

This will allow you to simplify it to just a single term which you can evaluate.

Hope this helps,
Stephen La Rocque.

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