- Choice HWe know that $$sin^2x\ + cos^2x=1\\$$ $$\Rightarrow cos^2x=1-sin^2x=1-\frac{4}{13}=\frac{9}{13}$$
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- Choice HWe know that $$sin^2x\ + cos^2x=1\\$$ $$\Rightarrow cos^2x=1-sin^2x=1-\frac{4}{13}=\frac{9}{13}$$
## Skills you are tested for:

Was this explanation helpful?

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